I'm going to disagree with Michael. I ride 30 miles each evening on my trainer while watching Netflix, YouTube, GCN, etc. I don't have your awesome level of life experience, but I hope to one day. I think an indoor trainer is an excellent way to build mileage. If your condo has the room, you can really pile the miles on with one. If you can swing the cost, a
Zwift compatible trainer such as the
Wahoo Kickr is a great way to gain motivation. There are other similar options. Then jump on the bike weekends for longer training rides.
As for the bike itself you have to ask whether you will need rack and panniers or just a big saddle bag. If you need the rack I recommend a quality steel touring bike. If you just need a big saddle bag then almost any comfortable, light, reliable bicycle will do. From your use of the word "condo" I assume you are state-side so there's
Rivendell on the West coast and
Peter White and
Alex Meade in New England just to mention a few.
If you have your heart set on a folding bike, be aware you will work quite a bit harder on one.