Thankfully battery life seems to be improving inversely proportional to Moore's law slowing down. Going two years on the same battery used to be very challenging.
In this case I skipped one year of out five, and the last year I did feel better when carrying a power bank just in case.
My iPhone X didn't have the 80% charge cap IIRC. Using that most of the time, I suspect my iPhone 15 battery will last at least 4 years. Which means it's probably more likely to die from me dropping it.
Might have to stop using Nostr with ten relays over wireguard with 5G at some point :-)
The iPhone X never felt slow, unlike earlier generations. Though it helps that I don't play games.