Compensate for weekly TSS decrease due to changes in aerobic cross training?

This is exactly the quandary my husband and I are in! I find that the amount and type of skate skiing we do weekly (plus the occasional race here and there) it’s really easy to burn out layering on VO2 Max and Threshold workouts that the plan is scheduling for our eventual MTB/Gravel pursuits in the Summer. With the hills and higher paces, my skis come in more at the VO2 Max/Threshold efforts (or Sprint if I’m doing 4x4s) so wondering if I should be doing the opposite that a lot of folks are thinking/suggesting and be supplementing with more Sweet Spot/Recovery rides on the trainer??