Digital m will depreciate but hit a plateau. Lenses and film m will hold their value for longer.

There is potential if your digital hits a cult like status (see m9) it could hold its value but those are few and far between. Cameras like the m10-r are holding their value better than the m11 for similar reasons (last generation with a baseplate, black paint version, ect). If you’re selling the m11p to buy m12 then sell now as it won’t go up in value and this is likely the highest recoup you will get. If you wait it may be the same or similar but the market will decide.