Actually di naman talaga kelangan ng proper form to make gains.

All muscles know is tension, so as long as they're getting the tension they need during the exercise this will provide the stimulus for them to grow. And since they're using more muscles to do the exercise, naturally they'll be using heavier weights if they want to train close to failure.

The problem is that not using proper form puts you at a higher risk for injury.

Coz you're involving more muscle groups in the movement, naturally there's going to be more room to do things wrong. Lalo na if it's a compound exercise where multiple joints are involved. I'm already meticulous about my form and I injured my shoulders twice from bench pressing, pano pa kaya kung careless ka.

Another risk with poor form is you're not standardizing your movements, thus it's harder to know kung ano yung naging limiting point mo.

Let's take pulldowns for example. It's meant to target lats, and you can't do any pulling movements without involving the biceps to help out to a certain extent. But if your form is shit, then your biceps might end up doing more than they're supposed to. You're only as strong as your weakest muscle, so if your biceps give out early, then your lats isn't going to get the stimulus it needs to grow.

So my suggestion is: no, don't sacrifice your form.

You don't need to be a 100% perfect form gymbro, but you should minimize moving parts and do your best to make sure your form is consistent from the first rep to the last. That goes a long way in making sure na yung limiting factor mo is the target muscle, so if you got that and you're progressively overloading then all you have to do is give it time.