Basically yes as you are building aerobic fitness. Lydiard is the god father here and had it pretty much nailed. I looked for a reasonably short description of his method and think the piece at this link is decent:
https://runnersconnect.net/coach-corner/base-training-running/
This describes the cornerstones of “base” which is Fartlek and long tempo along with some suggestions of how to implement.
Converting this to cycling, SST is tempo. Call it lower SST or 80% FTP (which is a proxy for MLSS). Fartlek is harder to describe but it’s a tempo ride with some short efforts in the 95-105% zone. As an estimate. I’d say just go for a nice ride, turn the legs over, but not a hammer fest.
A big difference between running and cycling is recovery. Running just beats you up more because of the impact and the upper body drive.