You can move the dongle to any machine you want. Since the dongle must be present, you can install the plugins on as many different machines as you want, and just move the dongle.
That said...
If the dongle doesn't work reliably (like it doesn't on my early 2012 Dell XPS 8500), you're SOL. No help. No fixes. Nada.
My first plugin purchases were Slate's. Dongle only. NEVER worked reliably. Not on Win10. Not even on the Win7 my Dell shipped with. I had real difficulty even getting the licenses off of it and back into the Waves cloud. Jeez, I hate Slate.
However, the PACE software (authorize to PC) works great for me. If a plugin requires the dongle, I pass.
FWIW, I go ALL the way back with PACE. I had two different PC-DOS apps that had dedicated Centronics (printer) port dongles. Bigger than a Zippo lighter. Each wanted to be first in line. I was always unplugging my printer and swapping dongles.
Even though the PACE software licensing works for me, I still hate them.