It uses the same public key unless you manually change it. You don’t get the rolling keys provided by other systems
I don’t think I understand what you’re implying. Are you arguing that PGP implements less secure operations because it doesn’t have perfect forward secrecy? As far as I know there’s not much out there in terms of encryption schemes for data at rest which includes PFS. Even AGE didn’t have it last time I checked. If you know about something that does provide PFS for data at rest, let me know
https://en.m.wikipedia.org/wiki/Signal_Protocol
https://en.m.wikipedia.org/wiki/Double_Ratchet_Algorithm
https://en.m.wikipedia.org/wiki/Elliptic-curve_Diffie–Hellman
The signal protocol works on double ratchet that works on Diffie Hellman
This is a good read. I think it’s a good solution if it can be implemented properly. Are there applications you know of that allow you to personally (manually) encrypt text and communicate with another person like GPG does?