If you want a complete unit with custom hardware and tuned custom software, look at MikroTik. Solid hardware, dependable software, good support, good community.
If you want to build your own, grab any multi-ethernet micropc from aliexpress and install OPNsense. Cheap and flexible. But you’ll be on your own once (not if) something fails.
Both of these are essentially pro-level options with lots of headroom to build up to advanced services. I’d stay away from OpenWRT which is essentially just an open source consumer grade wifi router image. You’d be replacing your crappy (but supported) router with the same thing just without support.
One other option I would mention if you like nice centralized web ui’s, have a look at Ubiquiti’s Unify. If you can afford to go all-in on a Unify router, backbone switch and wifi access points, the combined management is really a step above the competition.

For actual hardware: Hetzner. For VPS there are many choices. Digitalocean is cheap and easy, has european data centers, and some decent value add services.

Visual Studio Code, with a syncing folder, a markdown plugin that suits you, and Claude Code to sort your notes for you. :-)

Hey claude, upgrade my kernel will you? Thanks!