Help me find something better

I'd like some help to choose a FREE (no free-trial or limited frames/layers) program where I could animate (preferably one where I could transfer my Opentoonz animation into it e.g as frames or mp4 etc) and it should also be potato-pc-friendly

I've been making an animation for about a week, it's only on the first sketch-pass, I'll make another sketch before going for lineart and shadows, but Opentoonz crashes constantly, the animation is never on-sync since it lags everytime I click on play, even clicking and dragging on the audio timeline has a delay, creating a new frame by drawing or clicking on it lags my whole pc (not with D tho). If it's THIS bad at the first sketch, I can't imagine how much worse it'll be.

thank yall for the help!!