And it's virtually impossible for the a P85D to show only 150 RATED miles at 100% and for it to still be working without having thrown some other fatal error.
What is your current rated mileage and SOC? Divide current rated range / (charge% / 100). For example, if it says 200 miles currently at 90%, then your rated range at 100% is 222 miles.
Starting somewhere in V9, Tesla updated the firmware and slowed charging down....a lot. I stuck with V8 for years to not suffer rangegate or chargegate. Unfortunately I wasn't watching chargegate too carefully and once they fixed the range issue I decided to upgrade my MCU to MCU2 which meant moving from 3 year old firmware to current firmware. You can see what it did to my charging over night with just one firmware upgrade.
It now takes an hour to go from 20% to 80%.
For medium long trips, we compensate by always charging to 100% before leaving the house even if we didn't need anywhere near that to get to the first supercharger on our leg.
During a long meal stop where I would normally have charged to just enough to get to the next supercharger and then left the table to move the car to make room for other cars and to not stress the battery more than necessary, I now just let it charge to 100%. i.e in cases where I wouldn't have charged fully but could have without loss of time, I now always do so rather than trying to take care of the battery by keeping high SOC charges to a minimum.
Tesla's change to prevent me from charging quicker when I need it has resulted me changing my behavior in a way that is way worse for the battery.