From gaming:
Hardcore Levelling Warrior - Neat art, fun to read, updates biweekly on Naver Webtoon for free. Ongoing.
The Gamer - good in the beginning got meh in the middle, well, check it and see if you like it. Might have annoying characters, been a while since I've read it, so don't remember. Ongoing.
1/2 Prince - hit or miss, terrible ending, but is a fun ride in the beginning if you like cross-dressing shoujos. Finished story at least so you won't be kept hanging.
My Darling Signed In - fun catfishing-themed shounen ai. Ongoing.
Sword Art Online - welll..... it's harem. Protagonist is a Gary Stu. Novels make up a decent read, but you have to overlook those, uh, _flaws_. Dunno about manga, anime is meh at best, novels are probably your best bet. I have no idea about status atm, you'd have to check?
For dimension travel:
It's a huge hit and miss depending on what you're willing to tolerate and what not. If you're into historical mangas, give Shut Hell a try - it's finished and it's a great story, albeit not a traditional "oh hey look op protagonist" one.
For female MCs Isekai De "kuro No Iyashi Te" Tte Yobarete Imasu and Suijin no Hanayome are decent reads. Just browse the "reincarnation" or "isekai" tag and I'm sure you'll find something fun.
Oh and give Dungeon Nursery a try! It's comedy ^^
Any suggestions for newer dimension travel or gaming manga? I'm cool with most of the usual tropes except *please* no useless side characters or love interests blatantly leaching off the MC, causing all sorts of unnecessary issues, or in any other way acting generally idiotic? All the manga I've tried w/this type of plot line recently have one or two of those and my frustration is giving me a terrible migraine.