Wait! Before you do that (it may be too late)...
Note 1 big thing - when you reset your trip odometer (either A or B or both), the MPG will reset (basically) to zero. This will also impact the distance to empty. Mind you - it won't be a HUGE swing (and 100 miles is not really a huge swing).
Resetting the the lifetime could help but ...
Remember also that your driving habits COULD have changed over the last 15 months or so - were you still commuting for work? Were you still making long trips? Or was everything just a few miles here or there to the stores, the doctor, the wherever...?
DTE will fluctuate on a trip reset and how your first few miles (ok, maybe first few dozen miles?) as the system recalibrates from zero to something...
My normal weeks (before and after COVID) usually will see about under 100 miles... so my DTE will usually pop in at about 300 miles. If I get to take a few longer distance trips with more non-stop miles, then my DTE will climb. If I fill the tank and reset my trip, the DTE will usually first come up based upon that last DTE and average MPG. But the next 50 or 100 miles will see a change (up or down) based upon those miles.