I’m going to give you a slightly different take than what I’ve seen so far. I have a Deck and a PC. I game mostly on the PC, but I love the Deck.
The 256gb LCD model is $400. You can buy that, save whatever is leftover, and save up for a nicer PC build down the line. The Deck will be great for you while you save.
Like people said, you might not be playing the newest AAA games, but those are expensive anyway. There are thousands of indie and older games that will run amazingly and will be cheap that you wouldn’t have had access to on the Xbox.