I haven’t had a single switch die since getting Ethernet surge protection between the modem-router combo and my switches.
I haven’t bought a UPS in a while but last time I did it had Ethernet protection but only supported 10/100. You may have to get a standalone data surge protector to get gigabit speeds.
A mesh system means the access points will talk to each other. The best way to set up a mesh is with wired backhaul.
A repeater/extender will give you about half the bandwidth a wired AP/mesh node will because it has to retransmit everything back to the main AP.
I live in a relatively dense suburban neighborhood. We have had extended power outages In our area, and I can tell you for a fact, our phone company apparently has battery backup capability at our DSLAM that lasts about 12 hours. If an outage goes longer than that, they can attach a trailer-mounted generator to power it, (as long as they keep it fueled)
During the great northeast blackout, I saw a Comcast truck parked next to a little worksite generator (probably 500-1000 watts) chained to the pole, I assume it was powering a signal amplifier on the pole.
I know it’s anecdotal but I used to have to replace my router or router/AP combo every 12-18 months.
The first router on the Ethernet protection ran for two years and was replaced because I wanted 11g
All the routers since then have lasted at least 7 years.
Maybe it’s snake oil, maybe not, but it seems to work for me.