And maybe when she's in-game, a group of four enemies focusing a single character won't immediately kill you (but I doubt it with how health doesn't increase EVER).
The way you've set up combat makes you feel worse than weak. Shar feels worthless with her crummy net and health pack that barely heals 1 hit worth of damage most of the time. I've had fights where Shar's entire purpose was healing herself because three of the four wouldn't leave her alone.
The combat is so limited in the beginning, that rng totally controls how much damage you take or even if you win. I've lost fights through no control of my own because all four enemies murdered Shar in the first turn from full health before her first turn came to use a weak medkit.
You say you want people to use tactics, when the only tactic that exists once you lose the other three aliens is that netted enemies give 100% crit chance.
For example, why doesn't Heat Blast have any aoe at all? He isn't limited to tiny fireballs. He has flamethrowers and wide angle fire walls, as well.
Why does Shar have no damaging ability? Not even an auto attack? She's a female based off a character who was incredibly capable in combat. The net deals around 10 damage even after I cheated her attack up to 14k. The medkit's max healing I've ever seen was 76 (and I've only ever seen a number at 70+ less than 5 times). And yet there seems to be no increase to her healing, no better medkits...nothing.
There's a difference between challenging and 'you rolled crit ones so you die'. And then the UC reward for a single fight is less than a single medkit cost. So you're actually losing money any time you heal until after the Hoes show up.
Then there's the damage. You go from taking 25-50 from the Bros. Then 25-75 from the Hoes. To 40-80 from the mechs... But because you can't increase maximum health or mitigate damage, eventually you're just going to get one shotted by the enemy that does 150.
There needs to be either health growth or damage mitigation. Even the diamonhead ability you can only use for a single map takes your only damaging character out of the game for the whole turn. Why is your only offense the one being your only defense? Spread the roles.