I feel like I can tl;dr this review by saying "There's a good reason everyone focuses on the funny bits and not the actual game" but that also wouldn't really do it justice.

C&C3 Red Alert 3 (I will never call it CNC because then it might sound appealing) is very 2008. Normally, people throw in a "delightfully" with that sentence, because we've hit that point where people are clamouring for the 00s, but I wouldn't really call any of RA3's eccentricities delightful.

Just to get the white whale out of the way first: Yes, the campy elements are omnipresent. No, I don't actually think they're that good. I love me some camp, but the thing about it is that it has to be sold through the performances of the actors. The difference between entertaining camp and morbid fascination camp is in the performances, and in RA3 they're... bad. Really bad.

This game's IMDB page is so star-studded that it probably drove a Sony executive to despair, but not a single person involved takes this game seriously. Everyone is visibly struggling not to break down in fits of laughter. According to Tim Curry, he didn't even see the infamous SPACE line until the moment it appeared on the teleprompter. Anyone affecting an accent tends to lose it every other line, and pretty much every female character stares into the camera with a look of violent discomfort when they're not speaking.

I think this game's crowning achievement is having porn-tier acting, except with a cast that's primarily comprised of people who've performed Shakespeare on stage. That's not something you do by accident, it takes herculean neglect to do. It's really not helped by the lines given to the women, which do in fact sound like they're from a horrible porn parody of C&C. Add in their outfits - again, bad porn parody - and the pinups that were shot, and this game is very much the bad kind of horny. The kind of thing that gets yer da going, maybe. I also have reason to believe Tarantino was involved with this game given how many of said pinups have the women barefoot.

What really stuck out to me, though, is that a lot of lines in the game just read like absolute gibberish? On a base, foundational level, the script isn't very technically sound. There were more than a few times where I replayed a scene just to be met with something that would be considered unacceptable in a High School discursive essay, let alone a game that likely cost more money to make than the GDP of some countries. It's not funny bad, like some of Netflix Cowboy Bebop's atrocities, it's just bad-bad.

As for the gameplay, it's in a weird rut where technically it's fine (I guess) but is hamstrung by a lot of little issues. Unit pathfinding is atrocious even by genre standards, to the point of making Universe At War look solid. In most games with pathfinding issues this stops being an issue in wider spaces, but RA3 has the dubious honor of having it be omnipresent owing in part to units often tripping over one another before firing. As such, naval combat is hell.
It's especially noticeable when using Attack Move - a command that's often messy even in better RTS' - since, more often than not, units will dance around one another before zeroing in on a unit they're weak against. Which is funny to me, personally, because this game's marketing billed it as an RTS that even non-fans could sink their teeth into, yet the tool which lessens some of the micro load is a massive hindrance.
There's also a bit of a strange curve in terms of balance. I know Uprising fixes it, but good lord the Allied faction just stomps over the other two. I've seen a few folk online insist that it's because they're micro-heavy, and I get that, but since I can do the micro (thanks, Starcraft) I was just left feeling underwhelmed when stuck with the infinitely simpler Soviets/Empire.

Lastly, there's the campaign, which somehow manages to be the most 2008 thing in a game which dates itself so openly. Unusually for an RTS campaign, it's more focused on handholding and setpieces than actually being an RTS, with some levels feeling more like an RTT game than anything. Levels trend towards the linear, with scant few allowing you to properly base build and square off against the enemy. Each campaign feels like it's comprised of a Starcraft 2 campaign's intro missions, but stretched out for the entire runtime.
That's assuming you can play them, of course. I don't know what the fuck the co-commanders are being fed on the PC version (I played it on Xbox at launch), but even on Hard they stole my battles with alarming regularity. It's difficult to even comment on some missions when the AI bulldozed most of the enemy and left me with only a token resistance.
The mid-mission dialogues also expose just how flimsy the whole campy thing is. It consists of little more than the actors staring at you dead-eyed, spouting off orders and occasionally parroting a national stereotype. Which, for Empire characters, usually tend to be racist as fuck. There's an attempt being made here to blend camp with functional dialogue, but the effort exerted is only slightly above "putting a plastic bag in the recycling bin".

All in all? 2/10 you can get the best parts of this game from googling "Red Alert 3 funny moments".

[POST-SCRIPT ADDITION]

Thought about it more inbetween psyching myself up for a Disco Elysium replay and crying in the shower over the tragic death of Gajumaru, my favourite big bunny and I realized something:

This game's camp doesn't work because it's so gratuitous and self-mocking that it has the same tone as a mock Visual Novel made by an irony-poisoned American. There's really not much spiritual difference between this and, for one example, I Love You, Colonel Sanders! A Finger Lickin’ Good Dating Simulator.

My biggest regret is that the developers forgot about this franchise.Probably, now it is impossible to make such cool satirical works without being hated. But that is still an awesome game for people who want to see how Japanese Empire strikes Soviet Union by landing on amphibious tanks in St.Petersburg or how north atlantic treaty forces teleport their aircraft carriers in the lakes of Switzerland to fight with Soviet submarines. Absolutely funny absurd which makes u laugh and at the same time it works good within this universe.
But behind this funny plot there is also well-functioning gameplay, which, like in any RTS, is something like rock-paper-scissors of units that oppose each other. A certain unit is only strong against a certain type of troops and has a vulnerability against another. For example, tanks do a lot of damage to armored vehicles and buildings of the enemy, but at the same time they do little damage to infantry, so the player needs to keep a balance between the number of certain units. However, no one forbids, playing for the Soviet Union, to spam a bunch of attack helicopters and just ignore the losses lol