I usually play PSO2 on my Xbox One X but I also have it installed on my pc. Today I played on Steam and from the official launcher I see there is now 1440p and 2160p resolution options with correct UI scaling options! There's a 1.8 and 2.2 option now. It works great! I originally edited my user.pso2 file to get 4K but the UI was too small with no work around other than bumping it down to 1440p. I had no idea they would actually addressed this.
Not sure if it was mentioned here already but I didn't see it and I figured some would be happy it's now officially supported with correct UI scaling and all.