Amazing improvements mate! Honestly I feel like you can actually use song 9 & 10 in a game. The first 40 seconds of song 8 also feels like it could be used for a mysterious shop theme for a roguelike or something XD
For music theory it's optional to learn but I highly recommend atleast taking a look at it (TAETRO has some really great tutorials on it that I find pretty easy to follow as a beginner). For most programs you can also set a scale & lock it so you can only place notes on that musical scale (I normally just set a scale & just follow my gut feeling XD, as long it's on-scale it should sound good enough!)
Also if you want to upgrade a bit from LMMS, I highly recommend trying out Ableton Live Lite (The Lite version is the cheapest one & it's honestly good enough for beginners), there's a really neat feature on the app, it's basically always recording your midi inputs so if you're just playing around & you found a melody that you liked, you can just capture it & you don't have to redo it again.
Keep going mate, it's alright to make slow improvements! Good luck on your future music making stuff!
(Also consider investing a bit in music equipment such as a midi keyboard or a decent IEM if you don't have one already!)