I installed Ubuntu Studio 64; which runs on top of a “low latency” kernel…
Do I have to use Jack in order to realize any improvements in latency issues?
I don’t look forward to having to learn Ardour5, or whatever was installed when I switched to Ubuntu Studio…
Another issue is that I run the latest 3.1.2 as an AppImage and have seen on the download page that Jack won’t work with an AppImage.
But, do I want to use Jack anyways?
I use Pulse Audio now, which works fine except for certain apps not sending sound through Bluetooth to my Bluetooth enabled sound bars (SM Player does, Audacity does, unless my browser is open with Youtube in a window, then it is a hassle, involving closing the window and restarting Bluetooth)
But, am I missing out on the benefits of a low latency kernel by using Pulse and ALSA insted of jackcntl and Jack?
Thanks in advance 
Probably not.
Latency is generally only an issue when using real-time effects (which Audacity does not currently have), and real-time instruments (which Audacity currently does not have).
Latency is relevant when multi-track recording, but only as far as it is important to set up latency compensation (which can be done with or without Jack).
I would highly recommend NOT using Bluetooth for audio work. Bluetooth is OK for general media playback, but the huge latency, and reduced sound quality can be problematic when doing detailed audio work. Better to use a good pair of wired headphones.