Well im not really a pro, lvl 17 also, but i use hacker abilities often.
Team patcher- dont really use it alot but it mixes healing and enhancing
Guardian patcher- I use this the most, pretty much just healing
virologist- personally, not so fond of it. Yeah you can root enemies, lower their tactics, and attack from a distance, their attack and defence isnt so great at low levels(1- 25 estimate)
TEAM PATCHER- use on team missions to upgrade your allies, stay away from fighting
GUARDIAN PATCHER- using this on team missions will help keep your teammates alive longer, some fighting is ok with this loadout
Virologist-it probably would be good to use on team missions so others can help you out of a sticky situation if you're not so great with this loadout, it have better offensive qualities than the others, but it drains your inner strength FAST.
I hope this helped you!!!