For the last 7 or 8 months my sweetie and I have each been wearing a Pebble Time. Alas, Pebble went out of business maybe two months ago. Real bummer because the Time was great and the Time 2 promised to be even better, even if they did sort of insist on providing a health app (which you can just ignore). Completely submersible to 30 meters.

Mine works much better with my Android-based Samsung Galaxy S7 than my sweetie's does with her iPhone SE. Apple ios does not like to play well with other children.

The bluetooth range is nominally 10 meters, which in practice means anywhere inside the house and certainly between the watch and anywhere you carry it on a bike.

I would think any smart watch which has a built-in mic will be able to do voice-to-text messages, which is a really really really nice feature, probably the one I use most often. Most any smart watch will display on the screen any alert or related notification the phone can show, so it will display text messages you receive and then you can replay. I understand that the Apple Watch can actually do real phone conversations, which means it must have a speaker too. It is also expensive. At the very least, the watch display incoming call info, which means you can check who an incoming call is from just by checking the watch. That's nice for putting the watch on mute while in a meeting at work but still note any calls you receive.

Most other functionality will depend on how the app on the phone behaves and what kind of notifications it sends. Some phone apps can simply send notifications and the watch will display them. Some functionality requires that the phone also have a partner app to what the watch runs. You'll have to do your homework to see if anyone has written the watch app or the watch/phone pair to do whatever you want. Google Assist-like voice commands can be done on my Pebble only via watch apps that support it, not so much AFAIK but there is one that I know of. There is a Pebble app called Nav Me which does turn-by-turn instructions on the watch, really nice, but it works though Google Navigation and I don't know how well GN works for cycling. There is an app that displays weather radar from Weather Bug, really nice for checking the local rain clouds when you are commuting and stopped for a stoplight but don't want to pull your phone out. You need to go to the iStore or Google PlayStore and see what kind of apps are available.