UH-60 Pilots, have you found the requirement to fly 5 hours, twice a week (to keep up with Aviation pilot standards), too time constraining?

5 hours a week is a little high. If you fly 9 hours a month (3 x 3.0 hr AFTPs), you will meet you minimum of 96 hours a year / 48 hours a half. That is without IDT or AT factored in.

I do recommend your first year back, make sure you aren’t squeaking mins. Get through RL Progression and get as much experience as you can. 300-400 hours, your interest in Pilot in Command (PC) should be observed, with an eval shortly after. Your first year back will set the tone for the rest of your career, so prioritize getting what you can. The hard chargers get the first looks for PC, Tracks, Full/time positions, etc. Good Luck!

I’m not currently in the NG, but in my experience you had to have about 110-140 hours cumulative a year, with a minimum amount of night time, Instrument (hood and/or simulator), annual flight physical, and required check rides. You had to have at least three take-offs and landings in 90 days, or you had to undergo a flight evaluation. To keep from wasting time, you had to manage your night time and instrument time carefully - otherwise it left you “scrambling” the last few weeks or months of the year.
Much of that time could be obtained flying to/from and during Summer Camp (you could get 30 or so hours during summer camp). The rest of the required time had to be done either during Drill weekends, or during AFTP (additional flight training periods) weekends, or at a pre-arranged time(s) during the week. Single pilot aircraft were much easier to deal with b/c you didn’t have to coordinate availability times with another pilot or crew chief.
The 10 hours you mention is merely the optimum number of hours you could expect for a typical Drill (or AFTP) weekend, which broke down into: 2 hrs on Friday night (night time), 2 hrs Saturday morning, two hours Saturday afternoon, 2 hours each Sunday morning and afternoon - for a total of ten hours. That could be about 20 hours in a month if you got ten during drill weekend plus another ten during AFTP weekend. Of course, if you could arrange for additional flights during the week there would be more time. Most NG facilities had lots of weekday “mission” flying to do which would usually be taken care of by “on hand” staff pilots....
Most flight facilities worked closely with the pilots and crews to minimize civilian job conflicts wherever possible. However, your employer is required by law to let you attend drills and summer camps. Some employers encouraged their employees, and some groused about it..... The pay was very good. Some pilots opted to try to live off their NG pay. Not sure how it is today.

Your job and their understanding will decide how difficult it is to maintain. If you live and work near the facility your unit operates out of it wont be nearly as difficult as if you live over an hour away.