If you are coming back from a long lay off and overtraining and injury the best approach is the one you suggest. Months of easy base building below your AeT. I suggest actually testing for this rather than going off RPE. It sounds very much like using RPE let you down in the past. So, what rely on it now?
Yes, the top end >AnT will not get a training stimulus during this base period but if you read all we have to offer in our book and this site you will see that high intensity training must stand on top of a solid aerobic base. You are fooling yourself if you think you need to keep hitting that system when you are aerobically deficient and coming back from OTS. At the very least this will delay the ADS correction you need and at worst will lead you back to OTS and injury.