ERROR: 1 RID allocations of type 'N5GLES37TextureE' were leaked at exit.
ERROR: Texture with GL ID of 12: leaked 4736 bytes.
at: Utilities (drivers/gles3/storage/utilities.cpp:77)
ERROR: Parameter "RenderingServer::get_singleton()" is null.
at: CompressedTexture2D (scene/resources/texture.cpp:1079)
WARNING: ObjectDB instances leaked at exit (run with --verbose for details).
at: cleanup (core/object/object.cpp:2047)

Well, yeah, something like that happens sometimes. Godot 4 isn't very stable yet. If that happens only on project exit and won't break anything when project is running I think you can ignore that errors.

You can also try to run project with --verbose to see if that leaks are caused by your objects or not.

What the errors are saying is that some resources (texture in this case) leaked at exit (allocated memory wasn't properly free). That may happen if you do not release unmanaged object (for instance you removed Node from scene tree, but didn't called free()). Resources (like textures etc.) are reference counted, so they should free memory on its own when all references are lost. In that case you may still cause leak by circular dependencies.

And what is that: ERROR: Parameter "RenderingServer::get_singleton()" is null. no idea, something is trying to use RenderingServer singleton after it is already destroyed I guess, but that doesn't seems like anything your code may do.