Buy haven, even that 7% reduction on all shots may mean that strix must take 3 shots at you instead of 2. This is massive since you have way more time to attack him. Buy nimble since it increases your movement speed making it easier to strafe.
Try to make him waste his ammo, catching him on an empty mag is like catching him with his pants down. Try to make him panic and use reversal leaving him vulnerable. Don't track him through his dash place your crosshairs at the destination.
DO NOT buy illuminate, it won't stop her from flanking you, instead, buy haven. Makes it so that it takes more than one one magazine to kill you adding reload time where she is vulnerable. Burst her down so she can't hit as man shots.
Jenos is very flexible and can fill in many roles (except frontline) with any loadout. Try to find his play style and adapt accordingly.flanking? Group up. Damage? Flank him in a group. Healer? Cauterise.