I wouldn't consider that universally true, except perhaps for B-die. But very few AM4 memory controllers will do 3800 (fully stable, not just gaming / boot-stable) without a lot of voltage and stress.
I have 32GB of Micron E-die running 3800mhz 16-19-16-18-36-58 with Cas 16 listed first @1.41v all day.
I had Hynix running 16-20-20 3800mhz @ 1.36v with Hynix CJR sticks 16GB. Rated memory stock is 3600mhz. It did crash after a few months so I backed it down to 3600mhz because that computer is not in my house. This was on a MSI B-350 Gaming Pro Carbon with the latest AGESA bios.
B-die is pretty nice but a complete waste of money based on what you get back from it. Nice to have, of course. I have 8GB of Samsung B-die which is not the same as B-die because those are 8GB sticks vs. 4GB sticks. Mine would run 14-14-14 @3200mhz all day. But crapped out around 3400mhz. Very old Samsung sticks. Team Group Dark Pro memory with the heaviest and nicest heatsinks I have ever seen.
Keep posting your deals, Larry.