I think my computer needs a better graphics card for it.
Yes, without official x265 hardware acceleration you are probably out of luck (unless you have a powerhouse workstation). I would rather go for buying a 4K UHD player and a 128GB USB 3.0 stick and playing that movie via your TV or preferably a projector. The Panasonic UHD players are very good at converting HDR to SDR and 4k to 1080p, so you can watch Star Wars 4K on any regular TV/projector and still have the benefit of better grain compression via the x265 codec and maybe even better colors.
Some UHD Players are getting cheaper already these days. The Panasonic UB-404 was under 200 Dollars the last time that I checked. Mine included 2 movies, “Passengers” and “Life”.
A projection cannot show really deep blacks. E.g. Christopher Nolan (of Interstellar fame) color-times all his movies with raised blacks for home-cinema to replicate the theatrical experience. For this reason he uses an IP for all his movies as the starting point. So colors and the grain are closer to theatrical prints then a scan from the OCN would have been.
Mike Verta on the other hand color-timed for rather deep blacks to hide the matte boxes in space. Because matte-boxes wouldn’t have been visible projected in cinema as well. So he was in a bit of conflict: Raised blacks as projected or visible matte boxes as not seen projected. I think that hiding the matte boxes was a wise choice. Because most people will watch Star Wars on the TV Screen and wouldn’t care that those black levels wouldn’t have been possible projected.