OP - after reading all of this it's really all about how much you want to spend i.e. do you spend more and future proof, or spend on only the spec you need to carry out your day to day tasks. I can only say that I have a work laptop with a 15.4" screen (I think) and it feels tiny and not nice to work on, but it is very quick (core i5 8th gen processor and was about £750 a couple years ago). I used to have a 17" laptop which was much better, but still doesn't compare with a 24"+ monitor. Upgrading your PC is worth a shot, and with my limited knowledge I was able to install more RAM into my Dad's PC some years ago, but without the knowledge you may find that upgrading one component may then mean that you have to upgrade others to keep up. So off the shelf might be a more expensive but less hassle solution