so much so that lower back pain / sciatica has been resurfacing in these past weeks
I used to have this problem, unrelated to any specific car model. I'm not a medical professional or ergonomist so take what I say with a healthy dose of salt, but the first thing I would do when you get in the seat is make the backrest angle higher than you are used to, then adjust everything else - distance to pedals, steering wheel reach, seat squab angle etc. around that. I had been setting the backrest way too upright.
I found by doing this you avoid pinching off blood flow to the lower back/thigh area.