Switching from MAF to HR drift

Hello! 46yo F, have been in easy mode for a year due to long Covid. 19:46 5k PR in 2021. Using MAF aerobic range I could only run 13-14 min/mi at 124-134 HR. Decided to try the HR drift (PaHR) method using Training Peaks. I’m using the process described in UA blog. So far I’ve bumped HR up to 140-150 range and I’m still at a -2% drift. Do I keep going? I still feel pretty comfortable during the runs. But the range is now way off anything Maffetone would support. TIA for any input.