Oof, there's many.

Let's start with my older phone (Moto G5s Plus). Right since I got it, the camera focus was broken. When trying to focus, it would just vibrate and make rattling noise. HOWEVER, I found a "solution". Hitting it just right from the back and shaking it side-to-side worked. I used it like that for 4 years.

My current phone (Poco X3 Pro)has many software bugs. Some I probably don't remember as getting around them is a muscle memory.
Let's start with audio. The left and right microphones are swapped. Thus I flip it around (left-handed) when recording videos. This actually affects a few different MIUI-powered phones as I found out.
Wallpaper bug:
This started appearing since I got my phone back with MIUI global instead of EEA after both MOBO replacements (yes, and both were in warranty). The lockscreen wallpaper gets stretched top to bottom after reboot, but isn't affected by resolution. Homescreen wallpaper gets stretched if resolution is different than native, otherwise it gets zoomed in.
"Fix:"

1. For homescreen, create a black rectangle with resolution of 1080x2400 and insert the desired wallpaper into it, but slightly smaller, in center.
2. Set it as wallpaper
3. Reboot the phone
4. When asked for PIN, lock the screen first, wake it up, and just then enter the PIN. This fixes the lockscreen wallpaper.
5. Unlock the device and stay on homescreen
6. Pull down the notification bar, decrease and then increase brightness

Done! The wallpaper now has correct aspect ratio, it's just a bit fuzzy due to upscaling.
Images created in Termux not visible to Google Photos:
Go into Google Files, rename the file to something else, then change it back. Done!

Files from Termux counting into "System storage":
Same fix as above.

Uploads to OneDrive from Android crashing:
The solution is to use Firefox in Termux. Yes, desktop Firefox.

Poco X3 Pro screen not rotating:
The "solution" is opening Accelerometer and Gyroscope in PhyBox

MTP reporting different timestamps:
I do backups with rsync. Unfortunately, I did so over MTP, not realizing the timestamps are adjusted in some odd way. Now, unless I wish to re-do the whole backup, I have to stick to MTP. Unfortunately, I had issues with gvfs on Manjaro, so I can't get CLI access to MTP.
Solution: Use Linux Mint for backups over MTP.

Memory card slot not working in Manjaro for 2 years:
Solution: None. Some update brought the drivers after 2 years.

School network being unrealiable:
Solution: Connecting to both Wi-Fi and mobile data at once and running my own HTTP proxy server in Termux.
Warning: The username and password isn't encrypted in case of HTTP proxy. The proxy will likely also allow access to localhost by default. I'd recommend to null-route those requests. There may be more security issues.

ProtonVPN client being mostly broken on Arch:
Solution: Connecting to ProtonVPN on my phone and running proxy server on it.

School proxy server limiting network speed based on MAC addresses:
This one was used long time in past and kept as a backup. Unfortunately, it was needed again. It limits the speed to around 0.2Mbps if the MAC is unknown, which among other devices includes newer school PCs.
Terrible solution: Cloning MAC of one of the least used ancient desktops and using that on my laptop. I also bought RTL8152B USB Ethernet adapter, and burned that MAC into its eFuse memory (permanent). Pretty convenient.

Ok, I guess that's enough.