Yes of course you do.
During the summer, I try to do a ride like this at least once a week. However, once CX season is getting close, I think it is important to do CX specific workouts. MTB race power profile is not like a CX course power profile. MTB is way more “on” or “off”. CX is much smoother, and very close to ftp for 45min to 1hour. I still do at least one hard/fun mtb workout per week during CX season, I just make sure that I am doing a couple of CX specific workouts too, and skills work at least once a week.