How do I start to study passively?

I learned english subconsciously- or more like actively for the majority of my life through video games and English content creators.

I find this method of studying fun, and is quite suitable for me. However there are lots of flaws- like there's almost no way to practice grammar (which is my why grammar is terrible) and several other flaws too I didn't even know what an Adjective was until 9th grade (which is the grade i'm currently in-)

I'm trying to study passively to improve my grammar and overall english. However I find the method quite exhausting, or perhaps i'm studying incorrectly?

I'll appreciate it if you have tips for learning passively, or a method that's quick in absorbing information and or perhaps some tips for studying grammar, idioms and collocations as well