Off season prior to IM

Burnout is very real for some people. Take at least some of that time off like you normally do and see how you feel. A few weeks, a month? See how you're doing and then consider working on something. Probably look at another smaller break after and then be ready for when the plan starts up. IM builds tend to rather big for people, so you do want to be feeling fresh mentally as it will challenge you later on.

Always refreshing and good for both your mind and body to have unstructured time after your season is done. I find 3-4 weeks off helpful then move into unstructured time where I would do what I wanted to do.  Doing those two different periods post race season brought me into training with excitement and ready to go.

IM is more than all about the bike. Two changes in training helped me the most.  First was running consistency and running 4-5x a week. First IM I did I was so fatigued by way I was trained. When I trained consistently with gradual building my body handled it better than what folks think as traditional training with 2 weeks of build an 1 week of recovery.

My 2 cents: take the time to do the other activities you mentioned you have interest in.  If you feel like it, include some easy runs here and there, if not, don't.  I find taking time away from SBR makes me enjoy it that much more when I can resume training.  Enjoy your break, life is too short to not have fun!