That's great! Over the course of a year i lost about 55 pounds and while that felt great. It doesn't really compare to how great I feel having a high level of cardio fitness.
I started out using a Garmin Fenix 3 as a fitness tracking watch and cycling computer. I really has all the cycling computer you'd want.... if you have the desire to use a fitness tracker as well. (steps, sleep, smart phone notifications, etc...)
But i recently switched to an Edge 520 and like it much better as a cycling device. Easier to read screen, easier to mount, more data on one screen, etc... My wife has an Edge 1000 and after using both, i think the edge 1000 is a bit of overkill. Larger screen and what not, but other than that, there isn't much difference in terms of data collection and options if you're not going to use it for navigation.
I've actually never used anything but my phone for ride nav. However, in about a month we're taking a trip to Hotel Domestique in SC for a cycling weekend. They have gamins sitting out on the front desk with preplanned routes in them every morning. Will be trying that soon.
The Edge 25 looks like a compact bare bones cycling device that has all the connectivity you'd need.
Once you get data in Garmin connect (or comparable website/app) you'll be able to connect that data to several other useful apps. My data initially goes into Garmin Connect, then it gets sent to MyfitnessPal to log my calories to my food logs. It also goes to Strava because it's a much larger digital riding community which most of my friends use. Since i was initially focused on weight loss, i have an Aria scale reporting weight data to a Fitbit app which is also connected to Garmin and strava. .....it's a tangled web, but seems to work flawlessly in regards to connectivity.
Rails to trails is a fantastic network of bike trails that continues to grow. Much more abundant in the NE and midwest than down here.
If you have an iPhone (EDIT: they have cases for other phones too) this is a great mounting option.
https://www.quadlockcase.com I used this on all my bikes. I don't like to carry my phone in my jersey pocket and it's totally stable in this mount. I don't mind the using the case every day either.