I would like to re-train in game programming and / or level design. I’m looing for recommendations on courses which will help me to build skills in these areas.
It depends on the engine. There are courses here which cover Unity, Unreal and Godot and a range of subjects too from blueprint to C++, gdscript to C# and areas from rpg to stealth to fps.
So it comes down to what you want to learn and for which engine.