Okay, so seeing that there really aren't many devices to choose from, a better question I think I should ask is
Is OpenWRT right for my setup?
I originally wanted to go with OpenWRT because it always comes up as the best solution for all-in-one devices and I didn't want to introduce too much complexity to my network (and I wanted to never use proprietary router firmware again). I only learned from this thread that OpenWRT is aimed at lower performance devices (thank you @diizzy) and that not that many devices support >>1Gbit speeds and/or WiFi 6, whether they are supported by OpenWRT or not.
So far, the only option suggested that had 10Gbit ports was the QNAP QHora-301W, and that's not supported by OpenWRT so far (thank you @shdf). The only other option I found by myself was the Zyxel NBG7815 (5x 10Gbit ports!) but that one isn't supported by OpenWRT either.
So, right now I'm flirting with the idea of getting an x86-64 mini PC and running OPNSense (which came up better than PFSense in my research), which I also only learned about from this thread, thank you again @diizzy. Some people seem to say that setting it up is somehow more difficult than OpenWRT, but I looked at some tutorials and there was very little that I wasn't familiar with already. It would come at a cost of higher complexity of an extra switch and access point, but in the end, I'd still be managing the same services one way or another. I'd just have to remember to be on the lookout for BIOS upgrades for the PC.
However, the number of options for mini PCs with integrated >>1Gbit support is still not very large. I like the Protectli lineup, but they only seem to have one device capable of 2.5G, and it doesn't come cheap (over double the QHora-301W that has two 10G ports). So I'd probably have to get an expandable PC to put in a 10Gbit networking card, which, for two ports, would still run me about the price of the QHora itself.
In conclusion, I really have no idea of what I should even be looking for. Please help.