Some Distros come with Nvidia drivers preinstalled and I have heard people being succesful with them
PopOS and Nobara come to mind. Nobara is very similar to Fedora, it is in fact based on it.
I did not really solve it. I looked around for a bit but found no good solution. The only thing that sort of worked was to copy the stream URL in Jellyfin and paste it into VLC Media Player, which could play the videos okay. But that was not really satisfactory for me.
In the end I installed a new OS on my PC which already came with the codecs to decode x265 preinstalled. I installed it for other reasons but it fixed also that issue and now I can play any video in the Jellyfin Media Player. I did not try if it also works in the browser. The OS I am now using is called Nobara.
I had a similar problem. For me it was because some of the videos were encoded with x265 which some client devices could not decode properly. Therefore the server had to decode them but it was not fast enough to do it.
I guess that is why on the Android device the videos are smooth, it can handle the decoding.
I went through switching recently. Anytime you log in somewhere I would change the email of that account, and integrate it i to a password manager while being at it.
Bit by bit you become more independant from Gmail.
As a bonus I also started using a service like AddyMail or SimpleLogin, so that I have different emails for different accounts. Quite easy to use.
Does Joplin do what you need?