anyone else find changing account name on youtube harder than the guides suggest?

Yes, because there are three different names and the guides blur them together. Your channel name is what shows on the channel and videos. You change it in YouTube Studio > Customization > Basic info. Your handle (the @ one) is in the same place but is a separate field and has its own availability check. Your Google account name is separate again. Changing it doesn't change the channel name on newer channels, and the other way round. Also: two name changes in 14 days, and if the channel is verified you lose the badge when you rename and have to reapply. That last one catches a lot of people.