Pixel 5 bricked after normal usage

TL;DR: My Pixel 5 won't turn on. Bootloader was never unlocked, therefore it only contains stock software. I think the last update it received was the March 2023 security update. I already talked to Google Support, they also couldn't help me. What happened: - I used the phone normally, browsing Instagram - The built-in "App timer" Android functionality stopped Instagram since I was using it for too long - Simultaneously, I had the app drawer opened, and the interface was a bit weird (other apps looked like they were in the foreground, but didn't reacted normally. A bit hard to describe and difficult to recall from memory) - I used the gesture to get to the home screen, all seemed fine again - (I'm mentioning this here because it's the only unusual thing that happened and makes me wonder if I ran into a very weird software bug) - I locked the phone via the power button and did something else - After a while, my phone vibrated due to a push notification - I wanted to have a look. I tried to unlock it. The screen stayed black. It did some usual vibrations though, as if just the screen wouldn't turn on but the rest works - The notification was probably caused by Signal Messenger, since I checked the message a while later on my computer - Since the phone didn't react, I kept holding the power button to turn it off - Due to the first vibration, I'm still pretty sure that at that point in time the phone was working, just with a turned off screen - The phone stayed dark. No Google Logo indicating a boot process - I connected it to a charger, multiple times trying to get it to boot by holding the button for >1 minute - I connected it to my laptop. I know that I enabled developer mode / adb debugging before, therefore: - Using adb devices, I can see that there is *sometimes* still life in it: Most of the time it isn't listed, but sometimes it shows up as "offline" or "unauthorized" (unfortunately, none of my PCs are currently authorized via adb.) - fastboot devices doesn't show anything The phone was charged, at least at 60% and I didn't experienced any battery issues with that particular phone before. Google Support also didn't had any more ideas, other than sending me the repair form. Since it's out of warranty, repairing it will anyway cost as much as getting a new phone, so I'm open to any radical ideas at that point. How can I boot the device again and make it usable?