Running On Potato Laptop and New Client is Waaaaaaay Too Laggy. (Even In Low-Spec Mode)

My laptop is very potato and I cannot run the new client. It doesn't run in Low-Spec Mode, and no matter how many settings I change it just doesn't work. The Legacy Client worked perfectly for me, but now that that's been retired I cannot play LoL while I'm away from my PC at home. Anyone else have this problem? Are there any fixes? I can't get a new laptop for now so I'm pretty desperate.