Honestly I'd say just start with Unity or Unreal (wow, what a shock! i know). I say those engines are the easiest to get into because of the overwhelming amount of support, tutorials, and assets available. There no reason that you shouldn't be able to make even the smallest game within a month with those engines. Just follow youtube tutorials and hold their hand until you can cobble together something without their help. Another easy engine that gets very little recognition is Godot. it's been doing pretty well for itself considering how fairly new it is. It's developers and community are very active and helpful, and the engine utilizes a python-like syntax that's VERY easy to learn. Gets updates regularly and its developers are always receiving funding. Oh and did i mention its open source? meaning you can make any edits to it without having to credit the original developers. And if you are fortunate enough to have a semi successful game, you don't have to pay any royalties like you would with unity or unreal. It has growing support for c# as well. You'll struggle to find any assets specifically optimized for the engine however, and tutorials aren't all that plentiful, but there's enough to get by. Also the engine is very small (byte size wise) and is not at all demanding on your system, so it can run on toasters like mine. Imma stop sucking Godots dick now, but here the gist of what i'm saying:
Unity or unreal: if you're just looking to mess around with game dev as a hobby. Tons of resources to learn from and free assets/scripts available.
Godot: I recommend for long term aspiring game dev. Open source with lots of customization, no royalties if you make it big, and easy to get into. Not as many tutorials as the other engines though, and only small niche scripts can really be found for free. After you become proficient with engine, it's just as good as any other tbh. Oh and it's one of the least demanding engines out there for us toaster users.
I don't recommend paying for classes or tutorials. Pretty much all knowledge can be obtained for free and most of those "teachers" got it for free before deciding to sell it to you. Just go on youtube, browse subreddits, and go on the official forums for all the info you need. (Of course look at the engine API as well)
Some sites for free assets:
https://www.textures.com
https://opengameart.org
https://www.freesound.org
www.archive.org
https://commons.wikimedia.org
Only search for cc0 materials unless you don't mind crediting the owners of the assets you're using. That's about all I can think of right now. There might also be some juicy stuff in the graphics section of this site. Someone may disagree with what I said earlier or just add on to my pile. I don't really care.