I aim to complete one 90min 2x20 interval session on the trainer per week, the rest of the week is allocated to other indoor/outdoor workouts (SST, under & over threshold intervals and LSD/tempo rides, about 10-12hrs per wk) so to ensure I get enough recovery between workouts I limit it to one per week and usually the first workout of the week following a complete rest day.
I train by HR and RPE and at 42yo my current LTHR is 169 (I test usually every 4 weeks, i.e. 30min TT and take the avg HR of the final 20mins)
Here is a screen shot of the session I completed this morning showing HR and cadence, I have a good solid 30 min warm up and then complete 2x20min intervals with 5min RBI and then cool down, I have an avg HR of 160 for both intervals and my RPE feels like around 16-17/20. At the start of each interval I bring my HR up into Z4 and try to hold it mid zone and keep my cadence at about 90-95, towards the end of each interval I try to ramp it a bit, especially during the final interval after which I am pretty cooked.

How does this look in terms of being a good example of a LTHR workout, should I be aiming to push and try and maintain a higher avg HR during each interval i.e. deeper into Z4 closer to my LTHR?
Thanks for reading.