None of the game engine add-on works in blender 2.8

I started using Blender from version 2.78 and then switched to 2.8 while learning how to use it and modeling assets for my project. I made a character mesh with MakeHuman and imported it in Blender 2.8 with the addon “Import-Runtime: MakeHuman Exchange 2”, v. 0.30; I added details, rigged it with the skeleton from the addon Rigify (but not switching to a metarig), and made some animations. I tried to export it to Godot 3.2 in the gltf2 format (the only which should work properly) after not having success with the add-on “Better COLLADA exporter” and “Blender ESCN exporter” (neither compatible with Blender 2.8), but beside materials not showing correctly and some bone constraints not working, the mesh went not along the skeleton during the animations. I tried Panda3D, but I dropped it because all the add-on made for it not work in Blender 2.8 (e.g. “BlenderPanda”). I viewed UPBGE and Armory3D, but they looked too experimental and not ready for 2.8. Lastly, I put my attention on Unreal Engine: i tried “Blender for Unreal Engine”, v. 0.2.6.2, but in addition to the non-functioning of the download link, I succeded in installing it but it don’t work properly (the right panel not appeared).
Not having the intention to try also Unity 3D, how can I export from Blender 2.8 a static object with a material made in Cycles or better a rigged object with animation in the most faithful way possible, without having to make excessive changes to the work at each import, considering that do I work alone and in my spare time? I would prefer to use Godot or Unreal Engine 4.

Given that you’re not actually using the game engine, this thread would seem off-topic, however I’m struggling to see a forum suited to support on using addons.

Ultimately, if the addon developers have not made a 2.8 version, then unfortunately you’re out of luck.

If you’re using a recent version of Blender (2.81+) then I would expect for Principled BSDF materials and animations to work correctly. Check the addon manual first, to be sure the materials and animations are set up in a way the exporter supports.

If, after doing that, your model works in https://gltf-viewer.donmccurdy.com/ but not in Godot, you’ll probably want to file an issue on Godot itself. If the model doesn’t work in that viewer, I would suggest filing an issue on the addon, at https://github.com/KhronosGroup/glTF-Blender-IO.