My suggestion is to double down on what you know already (iOS, swift, etc) and do homework on about 10 companies that pay well and have a need for that skillset. Then, a couple months before your bond gets over, approach these companies and start interviewing. If you are good, you will get at least a couple offers and will be in a good position to negotiate.

Note - the key is to approach these candidate companies more or less in parallel, and not serially. If you have multiple offers, you have a much better chance to make much more than what you are making today, compared to learning a new skill at this point.

It sounds like you're determined and self motivated, you're off to a great start! Nice work on getting downloads with your Android apps!

Since you seem to have a lot of front end and app knowledge, personally I might suggest getting more familiar with back-end as a service technologies like Firebase, etc. You could then create apps/web-apps that scale without knowing loads of back-end architecture practices.

To get a good spot in a next company, practice explaining your accomplishments to date succinctly, meet people, apply to multiple companies and get multiple offers lined up.