ME/CFS or long COVID and managing PEM with cancer treatment

I have ME/CFS and I am wondering if anyone else here has gone through cancer treatment with this condition or something similar like long COVID that also features Post Exertional Malaise.

Right now leaving the house for one basic appointment like a blood draw requires three days of bedbound recovery time.

I am concerned that going daily for seven weeks for radiation treatment will cause the ME/CFS to become much more severe.

The last time I exerted myself to try and return part time to work, I became bedbound for five years.