Possibly controversial but... Hot Ones.

I prefer the older videos with less/no post production effects. I tried watching the interview with Elijah Wood but the fading video overlapping, music, zoom ins/outs, the voice echoing, and I couldn't deal with these stupid transitions. Closed the video and haven't got back since. The channel has one job and that is to make people eat progressively hot wings but the stupid post production effects ruin the video quality and make the whole interview less engaging. COOL IT SEAN!

Their content is good but how it's presented is garbage.

Jimmy Dore. Started watching in 2015. He was consistently about progressivism and brought awareness to causes such as Medicare for All. As the channel grew, he slowly became more deranged. COVID came and he found a larger audience spouting anti-vax dog whistles. The channel is now tabloid anti-vax, pro-putin, hot garbage.

Not sure if this counts, but I'll nominate Unidan.

Hate to say it, but Wintergatan and his Marblemachine X. In the earlier days his videos were an exciting mix of mad genius, cool music improv and crafting. Then he became obsessed with making the machine play tight, precise music to a level that is beyond what anybody in an audience would be able to hear, and it became obvious that the machine would never get finished because he was stuck in an improvement loop.

Cinemassacre/AVGN.

not a youtuber, but I genuinely enjoyed babylon bee and the daily bonnet for parody news about christian and mennonite culture. the humor was always inward. now its all propaganda

Mark Rober with CrunchLabs. I feel like he's sold himself into a more corporate world and isn't producing the same caliber of content he used to.

Jake Tran. His old videos were pretty cool. He went downhill ever since he tried to convince me that drinking soy milk turns people into femboys and losing sperm cells.

Idubbbz. It's fine that he grew out of his edginess, I largely have too, but most of his videos now just feel like he needs to pay the bills and just cranks something out.

SVSeeker. At first it seemed like a really inspirational channel about a guy building a giant boat in his backyard in Oklahoma that was going to be used as a free to anyone research vessel, but as time went on everyone slowly realized the dude had basically no idea what he was doing and was super hostile to anyone telling him otherwise. Now it's been two years since lunching the boat and he has done none of the things he promised to do with it (like even leave the coast) and it seems pretty clear everyone got duped into helping him build a retirement house boat instead of a research vessel.

Andrew Callaghan sad to say because I was a huge fan and I guess there's been actual rape allegations come out although he hasn't been charged with anything so who knows. That style of journalism I just love so much and he is so good at it so it's a shame.

George Lucas

Joe Rogan.

Since nobody else is saying it.

The only two I ever watched where this has happened and not simply them just up and disappearing was JonTron and Onison.

And it's understandable why the quality went down. Not only did I grew up, they were both accused of and/or involved in grooming or some shit.

I was a big fan of Illuminaughtii/ Blair Zon for a long time. Now she's so controversial, other creators make content on her.