Heres a test VFX shot of Rey shooting out Force Lightning instead of the Force Push to signify her instability, the compression makes it look slightly weird but it’s okay: https://streamable.com/cqtffo
I think for the effect to work seamlessly it would need to be more subtle, like tiny tendrils running along her fingers like in the Palpatine scene accompanied by a little sound effect. If the effect gets large enough that Rey would have noticed it visually, it’s gone to far imo.
If she doesn’t notice it then it completely negates the entire point of the proposed change. It’s meant to give her another reason to leave to Ahch-To.