If you think you have regained enough fitness to take the 4DP fit test, I’d do that. The Half-Monty is your next best choice. You can also manually set (or even delete, I think) your thresholds. With these options, you could keep your history (as fuel for fitness goals!) without having unrealistic workout settings.
Wahoo RGT will also give you an option to adjust your FTP based on your performance in a ride, so that could be another option - select “Just Ride” and see how it goes.
I did the Half Monty after several months off then scaled my NM and AC numbers down by about the same percentage drop I had in ftp and MAP as measured by HM. That got my heart rate in the predicted zones set on the subsequent workouts.
After a month or so, I redid the 4dP test. This seemed to work pretty well at letting me start over.