Not sure what you mean by a side hustle.
Are you looking to earn a few extra dollars and just get by?
Or are you looking for something with opprotunity for growth that can be developed or be used as a stepping stone to a full time parnasah?
In any case, there is also the out of town kollel option.
I do not know how much you are getting in kollel, but out-of-town kollelim usually offer way above in-town standards. Could give you another good few years of full time learning.