When I'm playing on 1.12.2 on the newest version, it lags the game like crazy, and it freezes and sometimes crashes the game at times.

But this doesn't affect 1.7.10

Try to set forceShadersOff to true, Particle_Rain_DownfallSheet, foilageShaders and Particle_Rain_GroundSplash to false.

those didn't really affect the game, it was just the graphics and smooth lighting, performance increased a lot, gonna add the better fps mod for a high fps improvement.

Also if you turn off storms targeting players, storms will actually change direction.

and now microsoft wants to buy github great

Can't help without a crash report, sounds like you fixed your performance problems anyways "it was just the graphics and smooth lighting"