Run it inside a Windows 10 (LTSC 2019) virtual machine (VMware or VirtualBox). Snapshot the VM before installing v21. When the emulator inevitably corrupts its RSLinx driver, you can roll back in 5 minutes instead of re-installing for 2 hours.
Rating: ⭐⭐⭐⭐ (4/5)
Automation Engineer (Legacy Systems Focus) Rslogix Emulate 5000 V21l
(Deducting 1 point for installation pain and lack of modern OS support). Run it inside a Windows 10 (LTSC 2019)