I'm happy to announce that Windows NT 3.1 is running fine on real hardware as new as a i5-4570/16GB RAM/500GB SSD + Asus H81M-C motherboard.

This particular motherboard has SATA > IDE legacy mode (the SATA port presents itself like a ISA bus IDE port, I/O at 1F0h, IRQ14 (170h, IRQ15 for secondary)) which is 100% compatible with the less sophisticated atdisk.sys included in NT 3.1. The disk must be physically connected the SATA port 1.

I struggled finding a working PCI networking card (Realtek 8029AS cards didn't get initialized and a semi-working AMD PC-NET card could be initialized but did not work in real world)

To my surprise, I found a Winbond 840 PCI 10/100 LAN card with NT3.1 drivers.

Once connected... it doesn't look so bad for a 1993 OS:

I can read/write files on my shared HDD connected via USB to a 2020 C6U TP-Link router. (might hang, but mostly works)

Also, I can print some plain text to my Epson L110 printer. (wirelessly connected via a Epson print server)

Couldn't get online, but I'm working on it...