It's in proton 11(beta) and proton experimental, which are both available on the deck in the compatibility menu for games. I don't know when proton 11 will move past being beta.
Two plugins you may want to consider:
AutoSuspend - you can set the deck to automatically go to sleep at 5% or another threshold, to prevent the deck from dying while playing. I believe you can configure additional low battery alerts in it as well.
MangoPEEL - The deck uses MangoHUD for the in-game performance monitor. You can use MangoPEEL to customize those monitors, so you can change one of the the deck's monitor labels to just show battery percentage, battery percentage + remaining minutes of battery life, or something similar. I can't remember if an actual battery bar is possible, but it's probably not.
I think you just need the install script, and then it will download the plugin.
The dev recommendeds using the command:
curl -sL https://raw.githubusercontent.com/MuteMotion-Tech/MuteMotion-SteamDeck-Shim/main/install.sh | bash
Which just downloads the install script (readable here) and runs it. The script downloads
And extracts it to a new folder in your decky plugin folder, then sets permissions for it, and restarts decky.
iOS has it built in as an accessibility setting apparently, on Android there are multiple apps like KineStop that offer some version of it.
He has a son who will supposedly take over, but we'll have to see how that goes when it happens.
The usual rule with denuvo is that if you change proton versions 5 times within 24 hours, it will lock you out for 24 hours.
As far as denuvo can tell, every proton version is a different PC, so they don't want you sharing the game between more than 5 different PCs per day.
If you have an OLED deck, the LB button switch is actually part of the joystick, and is very easy to replace. There could also be something wrong with the button mechanism, you'll have to look and see.
If you have an LCD deck, the LB button switch is actually on the same daughter board as the dpad/etc and will be harder to replace.
Honestly, it sounds like you've been spending too much time in some online communities that are doom posting about everything. Do things suck right now? Yes, but they've literally sucked for as long as human society has existed. Things can always be better, or always be worse. However you can't just sit around passively waiting for the times to change, or your life will suck.
The single biggest factor in whether your life is good or not is you and your actions. Don't let things outside of your control convince you to give up. Do the best with what you have, and I promise you that you can find fulfillment and happiness in the life available to you.

Required grown up photo.
If steam did allow transfers this way, I can imagine it being a new type scam where people fabricate death documents to steal steam accounts.
Some people are saying this is good, but Microsoft recently changed my default search engine to bing "In case it was accidentally changed or changed by another program". I have zero faith they won't abuse this, they are becoming ever increasingly pushy about using edge and switching to bing.

When the deck goes to sleep, it does the suspend animation, so you know it's going to sleep. If I remember right you'll also have a notification in the bottom right of the screen saying low battery or something similar when it happens.
If the deck is asleep and gets low on power, nothing will happen. I guess if you wake up the deck with the power low enough it might flash the low battery notification and go back to sleep, but I've never had that happen. I had mine set to auto sleep at 5% and I never tried to wake the deck back up before I plugged it in after the auto suspend.
I was mainly using it back when there was a nasty bug that the deck dying from low power could result in the CPU/GPU being permanently throttled to 400 Mhz, effectively making the deck useless.