I feel like you are approaching this wrong. You buy a laptop so you can be mobile. This is good if you travel or even just in an office where you might have to switch rooms (e.g. a meeting room). If you don’t need to be mobile, then you don’t need a laptop.
Some applications will restrict you to using a PC, gaming for example, or anything that needs a big GPU. In this case you don’t have a choice.
If you get a laptop, please, buy some peripherals. Get a docking station, a proper screen, a good keyboard and mouse. Pay attention to ergonomics. Dont give yourself RSI or back pain.
There are already quite a few approaches to quantum safe encryption. We’ll just have to switch to different algorithms. It’s really nothing to worry about.
EDIT: Ignore the below, I suck at reading.
~~The above comment is wrong. Its open source and its on Fdroid, you just have to add the IzzyOnAndroid repo https://apt.izzysoft.de/fdroid/.~~
~~Here’s the source code for liftoff: https://github.com/liftoff-app/liftoff~~
Tunic?