Agreed, but *losing* PPs is less clear.
It is clear that your unadjusted magic rating give magicians free spells.
It is less clear if magician lose spells if their magic rating goes down.
...how to handle the PP-gap.
Using adjustment points on magic as a physical adept is not as bad as you seem to think...
Using adjustment attribute points to raise magic rating during chargen is rather "cheap" in this edition.
One of the benefits of walking out of chargen with a higher adjusted magic rating is that you can bind more focus levels.
Spending karma to bind Qi focus is almost always the cheapest way to gain access to more power points.
Compare two physical adepts that both start with unadjusted magic rating 2 but one (A) also have an adjusted magic rating of 2 while the other (B) have an adjusted magic rating of 6.
Total karma cost for A to get a total of 10 power points (8 extra power points):
Bind force 4 Qi focus = 8 karma
Bind force 4 Qi focus = 8 karma
Raise magic to 3 = 15 karma
Bind force 4 Qi focus = 8 karma
Initiate grade 1 = 11 karma
Raise magic to 4 = 20 karma
Bind force 4 Qi focus = 8 karma
Bind force 4 Qi focus = 8 karma
total cost: 86 karma. Current magic rating of 4. Max magic rating of 7.
Total karma cost for B to get a total of 10 power points (8 extra power points):
Bind force 4 Qi focus = 8 karma
Bind force 4 Qi focus = 8 karma
Bind force 4 Qi focus = 8 karma
Bind force 4 Qi focus = 8 karma
Bind force 4 Qi focus = 8 karma
Bind force 4 Qi focus = 8 karma
Bind force 4 Qi focus = 8 karma
Initiate grade 1 = 11 karma
total cost: 67 karma and 4 adjustment points. Current magic rating of 6. Max magic rating of 7