I've made a few random dungeon generators that have used a deck of custom encounter cards or spreadsheets. Decks were good for a thematic experience. Spreadsheets were for a more random experience. The latter did use encounter templates like solo boss, boss-boss, boss-minions, and all minions that would be randomly chosen (but weighted towards minions) and populated using an XP budget calculator bases on average party level and the number of characters.

It's a lot of fun. The narrative part was always missing, though. So, we would test out combat builds and synergies using it, calling it the Danger Room after the X-Men's holographic training facility.

Are you planning on using 5e or another rule system?

Keep us updated, if you get something going.