currently i would say there is 2 content creators that i would go to to understand a character POTENTIAL
1) jinjinx & turner. their breakdown is more bare bones maths and test, they genuinely go through spreadsheets of data as proof to you whats achievable and whats not
 BUT, you'd have to sit through hrs or wait for their tldr which is also pretty long and actually digest the information that they provided properly and make that judgement yourself.
2) tenha. albeit his tendency to just outright whale, he does test properly and transparently. If hes on food and buffs, he tells u so, he shows his gears and up his talent by batches.
 from childe onwards he tries to test the characters itself from con0 to con6 ramping the upgrades up periodically.
 so you pretty much get an idea how much difference a vanilla unit is to a stacked unit. if that unit is not big pp dmg, he'll tell you it isint, at least hes honest bout its potential.
Again, if players cant make proper judgement themselves after seeing all these information laid out for them by these 2 creators, i rest my case...lol
And i think another creator that is definitely worth watching would be Enviosity.
As for the others, i think you pretty much nailed em bout overselling a unit without proper transparency, not gonna mention em, but pretty much almost all aside from the 3 ive mentioned are guilty AF
Take every guides/showcase/videos with a grain of salt, and calculate/observe/decide for yourself if thats achievable by your own standards/preference
if it fits your bill, go for it and you wont have any regrets.
Glad to hear tenha is moving in that direction, in the early days, i watched one of his vid, I forgot which was it, but it did not really highlight the strengths or anything but just pumping the shit out of it and say its good
Overall, I really like all these discussion that has been going on about geo daddy, really learnt a lot from it.
PS: apparently his E's energy generation is bugged and mihoyo mentioned they are aware and is fixing it.