The weird dual mode KTC 5k monitor is on sale for $535. If you absolutely can only have a single monitor for Mac work and PC gaming this is probably the least worst choice.
https://www.amazon.com/KTC-Computer-Compatible-DisplayPort-H27P3/dp/B0FGX622GP?th=1
Amazon.com: KTC 27 Inch 5K Monitor, 5120 x 2880 5K2K Monitor with 65W Type-C Port, Dual Mode Computer Monitors Compatible with Mac mini, IPS Panel, HDR 400, 217 PPI, 135% sRGB, HDMI DisplayPort, Tilt, H27P3 : Electronics

Amazon.com: KTC 27 Inch 5K Monitor, 5120 x 2880 5K2K Monitor with 65W Type-C Port, Dual Mode Computer Monitors Compatible with Mac mini, IPS Panel, HDR 400, 217 PPI, 135% sRGB, HDMI DisplayPort, Tilt, H27P3 : Electronics

@paul I'm intrigued by the tilt-only stand. Looks like it is higher than the Studio Display, so may be OK for me, and I'd prefer it if it doesn't wobble. Doesn't seem to be available here in the UK though.