If you've got a computer with google chrome (browser) installed -
https://chrome.google.com/webstore/detail/stravistix-for-strava/dhiaggccakkgdfcadnklkbljcgicpckn?hl=en
Hope that works as it's a link from my browser & may be linked to my account... Stravistix gives you some of the extra functionality you get in strava premium, for nothing basically. Shows you how effective your training is, keeps track of your mileage, fitness & fatigue - you probably get most of that with garmin but I just prefer the layout & presentation it gives plus there's lots of info on what it all means.
As regards my 'journey' to fitness, I cut out lunch completely 5 days a week and did 4 years family cycling without thinking about weight/fitness much at all and inadvertantly lost a few kilos. Once I got the road bike I upped my game, bought some connected scales (we never had any scales in the house before, which in retrospect was a poor decision), a fitness band and used a fitness app to track my data.
I continued losing weight slowly but the real change came when I got the turbo and could get on the bike whenever I had time (I'm a fair-weather rider, to my eternal shame). I've been doing 4-8 hours a week which is nothing compared to people who commute every day for instance, but I've tailored it to suit my goals by doing workouts designed to increase fitness & FTP... I was dropping a kilogram every couple of weeks at first, then a kilogram every 4-6 weeks and kow maybe half a kilogram a month but that's fine, I'm happy with that!
If you're willing to go out whenever, it shouldn't be any different for you, just keep pounding away at 140bpm+ (do some short climbs, get out of the saddle!) and you'll be doing enough to have a good training effect on your body until you get to the next level... The first thing I noticed changing in myself was the recovery time; max out at say 170bpm, stop & time how long it takes you to get back to recovery of about 120bpm. garmin has apps for that too...
good luck!