I'm looking for a story where, in modern Japan, a business/sales/insurance (something like that) man ends up going through a portal into a dungeon world and talks with a dragon... I think. He also met a high school girl who was a streamer and wanted to go with him into more portals.

He either quit or lost his job, too.

The world knows about dungeons and has people whjo go through them, but the MC wasn't one of them at the start.

Edit: Found it after a few more hours, it's called Koware Skill de Hajimeru Gendai Dungeon Kouryaku

I'm a jack of all trades but master of none. Too many jars and not enough hands.