Even though Godot 4 is an official release now (not in alpha or beta testing anymore), currently the Godot 4.0 docs say the following.
Attention
Godot 4's HTML5 exports currently cannot run on macOS and iOS due to upstream bugs with SharedArrayBuffer and WebGL 2.0. We recommend using macOS and iOS native export functionality instead, as it will also result in better performance.
Godot 3's HTML5 exports are more compatible with various browsers in general, especially when using the GLES2 rendering backend (which only requires WebGL 1.0).
I tested it out with a minimal Godot 4.0.3 HTML5 export uploaded to NG, and verified that it plays fine from my Windows lappy but doesn't run at all and just gives an error screen about cross origin array buffers or some crap if I try to run it from a browser on an iPad.
Godot 3.5 and probably 3.6 work fine though, so continue to use those.
However, if I'm wrong about that and Godot 4 web exports can be made to work on Apple stuff, or if at any point in the future anyone notices that Godot 4 HTML5 exports start being able to run from Apple stuff, then plz post here and/or ping me (which posting here will do) because I modified the code for the Newgrounds API Godot implementation to work with Godot 4 and confirmed that it can do everything including cloudsaving correctly (if you run it from Windows). I can post that Godot 4 code, but for now I'm holding off because posting API code for a version that won't work on the web for a lot of people would be trolly.