Z2 after a workout

I typically do my workouts before heading to work on the bike. A typical workout is structured where I will have ~20 minutes of warm up, then get stuck into the work, then ride on to work.

Because of the location of terrain, it’s not possible to ride most of the way to my work and then do the efforts near work.

I often complete the rest of the ride to work (60-90 mins) at z2 and have wondered if this is productive or I should just put into a lower level of work.

I know that it can be useful to do an extended ride prior to a set of intervals/efforts for fatigue resistance, but wonder if it is counter productive to continue afterwards at low intensity.

Thanks in advance.