> It amazes me it’s so hard to find monitors around 210+ PPI.
You're in luck; several 5120 × 2880, 600 mm × 340 mm monitors at high refresh rates were announced at CES a couple weeks ago.
MSI MPG 271KRAW16
LG 27GM950B
Acer Nitro XV270X
HKC M9 Pro
Hisense 27GX-Pro