I ended up getting a Fenix 6s about a year and a half ago and I think it's about as close to a Pebble successor as things get these days. I get a comfortable week out of the battery, and a responsive e-ink screen with the basics covered plus a few more fitness related things (and a party trick of topo maps) the Pebble didn't have. I don't feel like it has quite the community support that Pebble had in terms of software (or the enabling thereof from Garmin), so it's not 100% the same but it's been working well for me so far.