You seem to have a serious paranoia about the household power being full of nasty spikes. In my 6 decades of life I have never experienced damage to any electrical or electronic device which would have a footprint of being damaged by poor quality 120V AC. Maybe different parts of the country have issues with. It seems that power in the Northeast USA is fairly "clean". At least in my experience.
Maybe you had some bad experiences with "dirty" AC power, so you just want to warn others about possible problems?
Linemen, Electricians & many others cringe @ that & say otherwise.
To start I & many others live where the Power goes out often for many reasons. That alone make many problems & why people shut off many things because when power come up again is often way "Dirty" as just HVAC & other heaters/coolers in other homes start @ same time. Worse if the outage includes some type of business(es) with big loads starting too.
Home etc is often Split Phase 240AC... Feeding that is ~ 7000v or 12000+v or even higher before pole/pedestal transformers work to get that 240v. Just a Branch of a Tree or a Suicide Squirrel Touching High Volt wires can cause a line to spike dip surge or all 3 happening fast often before the line might blow a fuse or breaker. That's 1 of Thousands reasons Outside of a Premise like Home or Business have power problems.
But my power is under ground... Often that doesn't matter or have Worse problems. Big 1 is many Ignore
811 & Damage or Cut Buried Wires & Pipes. Even when underground power @/near you often have pole/tower lines feeding your "last mile" so end result often have same tree/animal issues.
Inside a place have more sources of electric problems...
You can watch 120/240AC on an O-scope for Weeks to Years & never see most problems because of time duration of those problems. Surges & Dips can be only a few Cycles @ random intervals. Spikes can be a few Milli to Micro seconds slamming everything with Hundreds to Thousands of Volts also @ random intervals. Plus Most Test equipment uses TVS Diodes, MOV, & other parts to stop a Spike @ the Input Terminals before anything else sees the feed.
This is Why they make Power Monitors costing Hundreds to Thousands of $ use by Data Centers & more places for Decades to Track power problems that shows how "bad" main power often is. Enterprise Line Conditioners & UPS & software for them has Monitoring Features to record some of these events. Even if a Consumer UPS had this (News Flash, Many Do) most never install the software & the data cable.
NFPA Electrical Code & others didn't add Surge Protection in Load Centers @ a whim. These try to Block Spikes etc from Entering a Premise or between branches like HVAC or Electric-stove spiking other branches.
Even Relays, Motors, & more In a Product need "Flyback" Diodes, Snubbers, etc to stop back feeds & other problems when you turn them On & Off. Some DCC parts may have protection but most DC packs, motors & other parts don't. Old Track switch "motors," motorize RR crossing & more getting power from the track or fix power from a DC "Brick" can cause same problems because they often have Zero protection.
That's only a start of power issues to/in a house or device. Vehicles have similar to more power problems & big reason why many Fail @ LED "upgrades" to replace standard bulb types.
