Consider a NUC style device, like a Protectli Vault FW4B, and install opnSense or pfSense.

I have not used Firewalla, but from the screenshots the interface looks more simplistic than what I would expect from a several hundred dollar dedicated router. It may not be able to do everything you want. OTOH, pfSense or opnSense may have a steeper learning curve but more capability.

Whoever is downvoting posts critical of Home Assistant, YOU are the problem. How DARE people not like what you like. The audacity! /s

I switched to Hubitat after starting with and using Home Assistant for years.

The Hubitat dashboard is a bit of a basket case. Having to mess with widget spacing and scaling by hand, and not having it adapt to the size of a device display is really silly. The stability is the difference however. I have not had to remove and re-add a device since switching. My devices and automations have worked flawlessly, and the management UI is laid out better than Home Assistant. My impression is that Hubitat focuses the vast majority of their efforts on ensuring ZigBee and ZWave reliability. This very much improves spouse acceptance.