Thank you!
I'm sorry but is Minecraft java edition have to do with the switch?
I have found out that not doing it in full screen increases the fps, but the bigger you make the screen, the lower your fps will be. It was running really smoothly, but that was only because the screen was really small.
Kubuntu 19.10 with Minecraft 1.14.4 + OptiFine. Happened for me before I disabled raw mouse input.
The same issue also happens, if you set the motion and power nbt of Ghast fireballs, Wither skulls and Dragon fireballs to zero. The entitys go into the ground and re-appear in the air. When you exit the world and log back in the entitys stay in the air as intended.