https://f-droid.org/en/packages/org.dslul.openboard.inputmethod.latin/

TinyWall

Expect a wave of fingers cut off and eyes picked together with a stolen phone? Or kidnappings more likely?

Is there an unofficial Graphene OS ROM for S23? Because if there isn’t and you want to try it, the Pixel remains your only choice. Have you had a look at Zenfone (8/9/10)? When my S9 comes to its EOL, one of those will most likely be my choice. (I won’t lie, I prefer to have the 3.5mm jack on my phone!)

I’ve been happily dualbooting Win10/Mint for years on the very machine I’m writing from. Zero issues with boots, GRUB, no need for flatpaks, both systems work fine, both configs heavily customized.

What was your starting point? Having Windows on the machine already and installing Ubuntu on top of it? (that would be commonly regarded as the ‘correct’ order) If not, and you can afford to scrap everything, that’s what I’d go for. If yes, and it’s Ubuntu that’s messing up your dual boot, I’d see if Windows can be restored after removing Ubuntu, and then try a different distro (I’d go with Mint Cinnamon, it normally provides smooth install experience).