Mini split is the way to go. I put one in my basement for the boy where he does his gaming. I got a Mr Cool. It comes with a pre charged set of lines, and is really DIY. It runs off 120 volts. You just need to run some power out to the compressor. I did that DIY too, but an electrician can run the power and the mini split solution is for sure an easy install. I did it in about 4 hours start to finish. Works awsome.
I thought about a portable but they’re noisy and the exhaust pipe can’t be over a certain length. Where I would have had to exhaust it was too far.
I think I paid $1500 for 12,000 BTU. It also works as a heat pump in the winter.