Are gen 2 starters even worth it (beyond pokedex)?

Blastoise and Feraligatr have no utility (Blatoise is a worse Gatr which is a worse vaporeon).

Charizard is arguably better than flareon (double resist grass), if you manage to roll FS/OH. Flying moves also provide better type coverage for fighting, ground.

Typholsion is a charizard with same stats that doesn't fly and has worse moves. Therefore typing advantage is gone, and yes it is a worse flareon.

Meganium and Venusaur also have utility. If you roll VW/Solar Beam it is the best grass moveset. Punishes Rhydon more compared to egg man. Pure grass and grass/poison also provides occasional typing advantage that a psychic type may be weak to (although these scenarios don't come often)

EDIT: I stand corrected, I forgot Egg man can learn bullet seed now, I always thought it can only learn psychic quick moves. Therefore Meganium and Venusaur's advantages only reduce to their Grass and Grass/Poison typings.

Venasuar with double grass moves is close to best grass attacker in my opinion, barely losing out to BS/SoB Exeggutor. But other starters are farther from top spots which is kind of disappointing but they benefited from prior CP formula more than current. Less competition back then except for Vaporeon and Arcanine

Maybe forgetting the possibility of bad movesets on top of that?

To me they serve purely as pokedex entries. I did however power up my charizard, bc he looks cool. I use venusaur and ivysaur as prestigers.

So you get boored and have Vaporeons, Flareons and Jolteons only? PFFFF

I do use Flareon and Typhlosion as Attackers and sometimes defenders. Ty has more HP than Flareon BTW. And it has great attacks as Flareon, Overheat 160!

for me i have maxed venosaur with solar beam and maxed charizard with some 2 fire moves cant remember which one but for me are good against grass types and snorlax as for squirtle still waits for good obe but i have more than 400 candies so maybe i will have luck and get water moves. maybe evees evolutions are better but i dont really like them so i dont use them i only have one vaporeon anyway i plan to use these starters also but still long long way before that?

No you are not. At level 28 plus there are really only 10 or so mons worth powering up. The starters are worth using in nattle against specific mons but generally none of them are complete enough to be worth powering up.