Used ThinkPad under $1000

I'm coming from a PC with a 3080 and a i5-12600k. That limits my budget to $1,000 but I would like to keep it under $800. I need something that can multi-task and work on the go, thin and light. I would like a DGPU (if i can) but I also want a over 7hr battery life. I will use this laptop for travels and just light work in general like browsing and cloud gaming (ouch). I need to be able to upgrade the RAM to at least 32gb, and upgrade screen to something 120hz.

(nothing under 2017)

TIA