Wasn't sure why Youtube panels weren't working for me but it seems VRChat doesn't install VS C++ 2010 x86 redistributables for Youtubedl to run. I know most PCs probably do have it installed from other apps or games but coming from a PC with a fresh Win10 install featuring only Unity and VRChat, this issue stopped Youtube panels from working for me until I went into the VRC files and tried to run Youtubedl manually.
(It comes up with an error saying that MSVCP100.dll is missing)