I've been printing from my Raspberry Pi 3B for over a year now to my printer's controller. The only time it stuttered was when I overloaded the Pi with a variety of add-on's which I coded to do this, that and the other thing. (Seriously, I've mod'd my printer to death.)
But I re-organized the timing of the Conky scripts on the local TFT display so that no two of them ever run at the same time and it's happy. It doesn't stutter or have problems on the serial line.
Sounds like you already have the Raspberry Pi 3B+ so why not try it?
Note: If you have a delta-style printer, these are more prone to stuttering when combined with 8-bit controller boards.