I can’t remember if you’re able to save in the void glitch or not, but if you are, definitely save the game right before you enter the battle. Have a lot of poke balls in your bag and just try to get as many turns out of your pokemon as you can. If you have one, starting out with a quick ball would be great, then it you make if to 20 ish turns, timer balls will work well too. Inflicting it with sleep or paralysis would also be a huge help, but I’m not sure how easy it is to obtain those moves this early. It’s been a while since I’ve played the game, so someone help if you disagree with any of this.