I just put together a Supermicro SYS-E200-9B to run OPNsense on. It's a Pentium N3700 with Intel HD Graphics.
Unfortunately booting OPNsense sticks at "Booting..." after the splash screen. I found this thread about version 19.1 and it appears to be identical.
https://forum.opnsense.org/index.php?topic=11869.0
Using the same trick of:
set kern.vty="sc"
boot
Worked to get it to boot. I just wanted to pass this along that here we are over a year later and the same BSD bug is present, and immortalize it in case someone else runs into this.