Kidnapped Dragons - Korean, OP regressor MC but focuses on his goal of saving humanity through unusual means. Has a psychological aspect for both MC and the other major characters. Has a slow burn romance, no harem as far as I'm aware, incomplete ongoing translation at almost 300 chapters.
Breakers - Korean, finished translation at 231 chapters and 3 side story chapters. Transported into a game world, harem(mostly comes together towards the end), war and large-scale battles, and shounen. I enjoyed this one. Check out some of the author's other works if you like it.
The Academy's Deceased Ate It All - Korean, ongoing translation at 136 chaps. Transported into a game world, harem, ongoing/developing romance at the current point in the story, it's pretty good but not top tier. I enjoy reading new chaps to take a break from binging long series.
FFF-Class Trashero - Korean, finished translation at 428 chaps and 14 side story chaps. This story, despite being an all-time favorite of mine, is hard to explain
why I like it so much. A few reviews on NU say how the MC is one dimensional and stuff, and say that it's just a pure power tripping self-indulgence kind of novel(which it is, don't get me wrong), but I found while reading it quite a lot of between-the-lines meanings that really hit you on the philosophical side of things, and the MC's view of things was very broken but enjoyable to read. This story features an OP MC getting more OP as a bunch of crazy shit happens, and to be fair it likely won't be up your alley. Just read the tags and you'll see what I mean. Most people probably read it as a no-thinking wind down story, but I think the most enjoyment of it comes from seeing the hidden stuff. Hidden gem imo. One problem is that the translators for the last like 300 chapters took down their site, so you'll have to find a pirate site to read it off.
Lord of the Mysteries - I have been reading this book for months, and I still have quite a bit left to go. Wish I could read as fast as I used to. Anyways I feel I have to mention it since I've been really enjoying it. Finished Chinese translation at 1,430 chapters, one of the most popular Chinese webnovels. Sadly there's zero romance in it, but if you want a heavy and long story that's technically a xuanhuan, taking place in a European Victorian-steampunk kinda aesthetic, with secret societies and churches with actual gods, and a transmigration cloaked behind heavy gray fog, then you should check it out. Not a light read, as there's lots of info to digest, but the MC at least sums things up and makes connections for the many mysteries and secrets for us. If not, I would never be able to read it with all the stuff going on. Also the powers and the system they work on are very bizarre and very detached from normal Chinese stories, so plus for that in my book.
My Best Friend is an Eldritch Horror - The author is a chill dude, so Imma advertise for him. Original English, has 200 chaps rn. High fantasy where the magic system is based on making a contract with an entity from other Planes, and the MC ends up with an Eldritch horror. There's developing romance though it's not listed in the tags, no harem. Has a kinda save-the-world plot, MC's an actual good guy, imagine that. The author has a contract with a real good artist and has some really nice merch. The Discord server is also a chill place where you can see some of the designs. It's cool shit. This is also probably the most xianxia story on this list, because I remember the MC actually sitting down and meditating at one point.
Also all of these are male MC, if that matters to you.