They can be extremely intrusive and are always there, always reminding you that RPG rules are always transparently and explicitly in effect.
LitRPG is based on all the successful anime, manga (Japanese), light novels (mostly Japanese - basically text with some illustrations), manhwa (Korean), webtoons (mostly Korean), and manhua (Chinese) that incorporate video game portal fantasy elements. This includes but is not limited to isekai and often incorporates tropes from many sources - a common trope is qi cultivation (from Korean and Chinese media). I personally find LitRPG tiresome to read but I find the webtoons a pleasant diversion. The term itself is, rather randomly, based on Russian media along the above lines.
If you want to dip your toes in something LitRPG that isn’t going to go on for 15+ books and may never end, I would recommend New Game Minus by Sarah Lin, which is all about a fantasy villain who discovers (to his rage) that he’s a video game character.