Depends on the level of effort you want to put into it. I've been working on a hobby project with PostGIS recently, and I've found it very easy to get started (a few hours to get PostGIS running + import just the UK's dataset using osm2pgsql). But it's taken me months to get to a point where I'd say I'm pretty experienced with it.

Awesome, thanks for the tip. Osm2pgsql looks very interesting, the docs lead me Mapnik which is pretty much what I was looking for.

Importing OSM data into PostGIS is mostly painless with imposm3, probably because it's actually documented, unlike most other pieces in the tile-serving stack. The biggest hurdle is probably understanding both the OSM and SQL way of thinking.

Interesting, a cursory glance at the git repo for imposm3 looks promising. Which also lead me to https://mapproxy.org/ which the maintainers of imposm3 also created.

I understand your comment about sql thinking, in my day-to-day work I'm a bit of a reluctant sql developer (shudders in procedural spaghetti) but am gaining appreciation for being able to hand off aggregations and calculations to the db.