Wiser words have never been spoken! It's hard to work that sex muscle once it's been dormant for a long time but, as you wrote, if both partners want to put in the work then it becomes easier.

The scheduling sex part didn't work well for my partner and me, we needed to rebuild the desire part first. I think that's the big difference between bad sex and good sex. If there's a space to build desire between the two of you, then sex shouldn't be bad. Then it's about sexual intimacy, and that's a wonderful bonding agent and great workout routine!