For router check out the Turris Omnia [0]. Seems to be a good choice.

[0]: https://www.turris.com/en/omnia/overview/

That looks pretty nice. Too bad I didn't see this a week earlier since I just upgrade my home network last week.

Mikrotik is the most common recommendation probably but wifi speed is a problem apparently.

There were some other suggestions in yesterday's Ubiquiti discussion.[1]

[1] https://news.ycombinator.com/item?id=26628198

For firewall, I suggest an OPNSense box. You could run it on a thin client, a Protectli etc.

For AP, OpenWRT seems decent.

I use Mikrotik (or OpenWRT) for routers, but Mikrotik is not that good on WiFi. Peeople recommend Ruckus, but it's pretty expensive (and not that easy to get second hand in Europe, or Spain at least).

Is there any (good) brand with pricing between Mikrotik and a Ruckus that doesn't need a cloud connection?

Can you elaborate on your experience with Mikrotik wifi? What don't you like about it?

Is it not possible to just add in a separate WAP to the MikroTik device ?

I have happily upgraded several homes from Mikrotik and/or Ubiquiti to Eero mesh - https://eero.com/

"an amazon company" already makes some warning lights blink in my head. Do they have cloud integration of any kind?

It's cloud managed and sends network information to Amazon.