If you want silliness and pop culture references, Dungeon Crawler Carl should do the job

I would recommend Ender's Game as sharing a number of themes as well as being easy to read.

Old Man’s War is a really fun, easy read. The aliens are pretty creative and the basic premise of old people getting new bodies to fight battles in space is fun.

Bobiverse!

Off to be the Wizard by Scott Meyer, it's a blend of Sci-Fi and fantasy. Just a little bit different.

Check out REAMDE by Neal Stephenson.

If you want something with a game/tech black mirror like feeling, I recommend Daemon and Freedom by Daniel Suarez.

You might like Red Shirts. A self aware poke at Star Trek.

Mogworld by Yahtzee Croshaw follows a sentient NPC unknowingly living in a video game. It's not so much wrapped up in nostalgia and is a dark comedy, but the author takes the premise seriously enough. I've read it several times. Not many books like it.

Ring World by Larry Niven is a big departure from the genre of video game existence, except that it's the inspiration for the Halo series. It's a old fashioned sci-fi romp, the kind of thing that inspired ready player one. It's got super technical cool hard sci fi concepts mixed with an extremely colorful cast of misfit protagonists. Very readable.

Random, but Mrs. Frisby and the Rats of NIMH by Robert C. O'Brien is so extremely imaginative in the way it nest it's cast of talking animals within the real human world. (Yes it is actually sci-fi). The book is marketed towards children, but that was more an artifact of how it got published back in the day. It's extremely well written. The movie is cute but takes a lot of liberties.

Well, there's the book he ripped off, Snow Crash by Neal Stephenson

'Only You Can Save Mankind' by Terry Pratchett.

Do you want the nostalgia factor? Or just good, fun, SciFi?

I'd say maybe ubik, or snowcrash

If you mean similar as in the VR gaming aspect, look at Heir Apparent by Vivian Vande Velde. It is written for young adults so it's easy reading.

Note: I just looked it up and I guess it's a part of a (loose) series of books https://www.goodreads.com/series/71160-rasmussem-corporation

Doesn't have the nostalgia, but I enjoyed "How to Live Safely in a Science Fictional Universe" by Charles Yu in the same general zone as Ready Player One. It's playful yet dips toes into the serious or heartfelt at times. About a time mechanic who lives in his time machine with his dog, employed to traverse time and fix time machines of others.

Lucky Wander Boy is about a dude obsessed with finding an absolutely (fictional) bizarre arcade game he remembered from his youth called Lucky Wander Boy and ends up working for/with its creator trying to know more about the almost magical video game he grew up playing.

I didn’t read that series (referring to Ready Player One) since there was transphobic stuff the author put in the book.

But in terms of fun reading I would recommend the Monk & Robot series by Becky Chambers. It’s wholesome and heartwarming. It’s two sci-fi novellas.