With regard to The Holy Week I also found the heart rate zones way too high. Think I was in a steady state high Z2 when it was asking for Z4. It may well just not have been programmed correctly. I wouldn’t go adjusting anything unless you feel that the power target is consistently out of whack with your RPE.
I actually don’t set my LTHR in the app (and delete it after a test), that way I see what my heart is doing but don’t see a frequently incorrect bpm target. Just a quick tip/hack.