Do you know of any? Apocalyptic novels with dungeons? Perhaps, in a world that has already fallen to zombies or whatever, the MC survives because he has a dungeon at home? Or perhaps a system that allows him to go into one? Just trying my luck here. Is there anything like that out there?
The Legend of Randidly Ghosthound on Royalroad could be what you're searching for, a bit too psychological at time since he's talking to himself for entire chapter at time about how to go with this or that upgrade and evolution and whatnot but still not a bad read. And you can skip the chapter when it's too much introspection and not enough adventures.
Unlimited Power - The Arcane Path - Not exactly a dungeon, but the MC gets stranded on an island and has to fight off creatures that suddenly appeared, to survive. There's a system too. By the time he leaves the island, he gets really strong. I wouldn't call it a great novel, but it does somewhat fit your requirements. The Reincarnated Vampire Just Wants To Enjoy Her New Life - The MC has a dungeon as her home. She becomes incredibly strong because of it too. This is a lot closer to what you want but it has a 'gender bender' tag. Doesn't make too much of a difference though. It's a female protagonist novel for in all but one chapter. You can find both these novels on Scribblehub. It says that I can't post links so sorry about that.