I had an Issue for the longets time with my laptop with a ryzne 5 4600H and an radeon RX 5500M GPU where whenever I fullscreened Minecraft in a second monitor it just stopped working and crashed.
Fortunatelly, I had a solution, and it was to activate an option called "Triple OpenGL Buffer" or something like that. That may confuse a lot of people and I think it´s an issue that needs to be solved, as I found many people on the Mojan forums with the same problem but no reports here in the AMD forums.
Please solve the issue so that you don´t need to activate this option specifically in order to be able to play minecraft on fullscreen on a second monitor.