I defeated the final boss, it was quite difficult, but with some strategy and dedication, it can be killed, here's the strategy I used:
First of all,there's a reliable strategy to dodge the laser and get a hit in. When she starts teleporting, reach the top of the map, and the moment she stops teleporting, hold the down button. This will give you momentum for when she appears, meaning you will go too fast to get hit. Also, if you do this, she cannot send a laser to the bottom, so it'll be literally impossible to get hit.
To help with the timing, start counting when she teleport. She will do 6 to 8 teleports, counting will help you understand when you're in range, or at least it helped me. While holding down, try to get a hit in, you might hit too early at times, and for that I suggest either holding the hits for a split second more, or learning when to stop holding down, so that you can hit her while she's still using the laser.
Now onto the other moves:
An important rule to remember is that you should move to the top of the map only when she's teleporting, an all other occasions you want to stay in the bottom, because it's easier to dodge there.
For the hand attacks, you have to do a mixture of dodging and hitting them. Always throw an attack when you see them getting close, as there is a chance you will hit them even if you attack in the wrong direction. You will not see where the top hands are coming from, but for that there is no strategy, just reaction times.
For the raining move... good luck. I got hit twice by it during my fight, and if you get hit 3 times, you automatically die. Try to hit her every time she uses the laser and you'll have to go through less of these phases. Generally try to not get hit, but don't be desperate if you do. During my fight, this phase was played out only 3 times, and i got hit in 2 of them, so if you're lucky enough, you'll just have to do the same.
I think I hit her around 7 times, but sadly I did not count (and have no intention to go back into that hell).
Hopefully this will help someone, I really found no other way around it. My hacking skills are not good enough to decompile the binary code and remove hitboxes/create a god mode, even tho I know it's possible, maybe someone more skilled than me will do this in the future.
Until then, good luck. Also remember to buy the game on itch if you enjoyed it, I did even tho the final bossfight is bullshit, the game has a lot of love and care put into it.