TLDR: can anyone recommend a product to power a Raspberry Pi from a 12V SLA battery, so it continues to work during a power outage?
Background
I have a Raspberry Pi 4 running PiHole, including doing DHCP and DNS. My router and the fiber box are backed up by 12V SLA battery and a Sentry Lite, but if the power goes out we lose DNS so we can't use the WiFi easily.
I can have PiHole issue a secondary DNS address, but Windows uses primary and secondary DNS almost equally according to WireShark, rather than primary / secondary. I want Windows to use PiHole DNS unless it's unavailable, and I don't want to have to manually update DNS during an outage as if I'm not here my wife can't do that, and it's difficult on Android. There are a few possible workarounds to tweak how Windows does DNS, but I haven't spent the time to find an authoritative method to force Windows to use primary DNS. I'm interested if anyone has any thoughts there.
In the meantime, I'm looking for a way to run the R.Pi4 off the 12V SLA battery already right beside it. I could buy a generic 12V to USB-C converter like this one or a cheap AliExpress version, but I'd like something a little higher quality, ideally able to supply 5.1V @ 3A. There's plenty of options, like this and this but I'm wondering if someone has can recommend something they have experience with or have heard good things about.