I need to do the highest end workstation tasks I can do
Ok, fine so you want something fast/powerful
I don't care about how a 3900x is going to destroy my old ass hardware in every single way possible
Yet .. you don't?
I get it, you have a stupid fascination with a dual processor system. These days they are pretty much pointless for workstations, you can get MUCH better clockspeed (ie actual performance) in single processor workstation systems. Server cpu's are optimized for throughput, desktop/workstation cpu's are optimized for latency and responsiveness.
Everyone is telling you to use a single cpu workstation because it will be better for you.
You insist on using a dual cpu system because you have some child-like infatuation with them. Fine, get ahold of some old crap to build a dual cpu system and get the bug out of your system, but DON'T actually expect that system to be useful in modern tasks.
Oh, to answer your question, TrueOS uses the FreeBSD kernel (that literally took 2 seconds to google) so it will be the exact same as FreeBSD regarding any issues with ACPI, although issues with ACPI are really a thing of the past, definitely not something I'd be worrying about in 2019.