I can share some tangential experience. I started off as a game tester (mobile) at that as i really wanted to be a developer and wanted to break into the industry and i had read it was a great way to get in, to add to this , i was already studying computer science which aligned well with my aspirations. . I even enquired a uni which at the time was only one of the few to offer a degree in game development. This is pretty much great advice that was given to me - do not join a game development course , rather do a generic computer science course as it will keep your options open and you tend to learn more which can directly be applied to game development , but i think you are already latched on to a job so may not apply.
I looked up a lot of avenues to learn to write games & finally found a site (which i can't recall as this was a solid 15 years ago , may be
https://courses.gameinstitute.com sounds like it , but the course is so different now) and found a way to wink-wink get hold of their material and started to work through it , As i was working through the material i ended up realising i did not have the chops for it. Its a very exciting field which is at cross section of art , math , physics & programming. And i pretty much sucked at the first three and was average at best with programming. So after relenting for a year i threw in the towel and took up a straight forward developer role,for me it turned out to be a great decision.
So coming back to what you should be working on ? I would say pick an environment you are happy with , if its web , build some web based games, something simple like pong or say air hockey (
https://www.cbc.ca/kids/games/play/air-hockey). Here you will end up touching a lot of sub-systems , loading art , rendering , music - physics modelling , keeping score , events etc. Build a small game , from start to finish and you will have a full life cycle experience. let's say you have built air hockey , next think of adding networking to it , so you and a friend to play together and keep improving it. If you know python you can try this out at a glance the progression seems great.
Of-course , plan B is to pick up a full blown package like Unity or any engine off the shelf and go from there. Whist this may sound great, i feel you need to do the former to get a good grasp of what goes into making a game. Then you will find a niche you want to work on. May be you just want to do physics or sound or level design or networking or game engine.
Its a very rewarding experience when you finish your first game , i hope your experience is much better than mine lol.
Good luck!
