I've been experimenting with Godot. On a game I would call a Broughlike actually! I like it a lot as it feels a bit more mature than GMS2
Viewing post in what language/system/software are you planning on using?
So far I've been using the docs and they have been very helpful: https://docs.godotengine.org/en/3.1/getting_started/step_by_step/index.html
The docs are also open source so they are constantly getting updated by the community.
The discord is pretty active as well and has help/question channels: https://discord.gg/zH7NUgz
There are also lots of videos but I haven't watched any so I can't recommend any in particular but it seems they are pretty numerous.