Upon running minecraft with the mod an error code is displayed
Incompatible mods found!
Some of your mods are incompatible with the game or each other!
A potential solution has been determined, this may resolve your problem:
- Replace 'OpenJDK 64-Bit Server VM' (java) 17 with version 21 or later.
More details:
- Mod 'NoDespawn' (no_despawn) 1.20.x requires version 21 or later of 'OpenJDK 64-Bit Server VM' (java), but only the wrong version is present: 17!

I made sure to update OpenJDK to version 22 and have made sure that there is no other installation

should be version 21 for minecraft 1.20.5 and up, not 22 (or 21 is what I tested it with).
let me check though. I tested it before, and it worked (or I remember it working), but 1.20-1.20.4 run on java 17 while 1.20.5 and up run on java 21, so I might need to split 1.20.x into two versions.

tested working with java 21. I don't currently have java 22 installed on my system.
I will release a java 17 version for 1.20-1.20.4, though running 1.20-1.20.4 with java 21 does work.

I have now uploaded a java 17 version for fabric for 1.20-1.20.4

I uploaded it to curseforge, but if you don't want to wait for it to be approved, you can find it here
https://github.com/sebastianbhahn/noNametaggedPeacefulDespawn/blob/fabric-1.20-1.20.4-java-17/compiled%20jar/no_despawn-1.20-1.20.4.jar

(image added because I don't find github's ui to be very intuitive)