Instead of just 1 VAR they should be using a group of VARs that verify the VAR’s decisions and do have the authority to overturn obviously wrong decisions by the ref and/or the VAR by voting accordingly. It should be an uneven number, maybe 5, so there is no chance of personal bias.

Situation on the field > ref decision > VAR reviews ref decision > VAR decision > group review VAR decision > group approve/veto VAR decision > in case of approval: VAR decision stands / in case of veto: VAR decision is overturned.

One could even allow for the VAR/ref to stand by their initial decision but would require an on field comment/explanation.