In reply to the sheep:
My girlfriend has one of those, has never had another watch and thinks it’s great. In contrast, I’ve used an original Ambit, a F235 and currently an Fenix 5. Borrowed the Tomtom and hated it - uncomfortable and awkward to use.
To the OP: in your case I’d go for a basic Garmin - the 30 or 35 if you’re really interested in HR (probably worthwhile if it’s only a tenner more). Will do everything you want. Regarding days out and battery life, you’ll need to experiment - they may well do 8 hours on the default setting, they may not. This can be worked around by changing the settings, which is easy. To do so, switch the logging time from 1s to 1min. What this means is that the watch records your location 60x less a minute (ie one a minute alrather than once a second) and saves loads of battery. Trade off is that your track will be less smooth as it’s made up of less points. In all honesty 1 min logging is fine for walking, not really for running. Might not be an issue depending on battery life and the length of your days.
Regarding timing a specific section of your run, you need a lap function - even a £7 Casio has this so if a sports watch doesn’t I’d eat my hat/fire a designer. However, most watches will have an auto-lap function (Mile or km, depending on your units) which you’ll need to turn off for your laps to work properly. There’s a little more background but the same end - just turn off the auto lap. This then ends up in the file on Garmin Connect (or whichever brand of watch you gets software) and then pushed to Strava.
You can directly link Garmin Connect to strava - so upload your run/walk, and it will appear on strava almost instantly, except when the system is down.