Sunday workouts on 40k TT mid volume specialty plan has really long 60+ minutes at 85-95%.
https://www.trainerroad.com/cycling/plans/199-40k-tt-mid-volume
I’ve found SSB1 medium and high volume to deliver more than enough training to allow me to go out on the weekend and do really long work at high percentages of ftp (up to 2.5 hours).
After that I think it’s time to progress to start doing one long threshold effort per week.