I'm in a similar boat - I pretty much use the watch for HR tracking (as a proxy for stress), but otherwise keep things like the notifications disabled. This gets me about 20 days between charges
However the biggest problem is that the eInk screens seem to be a major failure point - even when working normally it seems to suffer massive burn-in making it unreadable after a few months.
My first watch had the screen die due to what I believe was trapped moisture (the weep-hole on the back is easily clogged) and just a few days ago my current watch also had the screen go bad.
It's really sad because the feature-set is almost precisely what I want, at exactly the price I'd like to pay