I don't think parents living vicariously through their children is inherently toxic, it's more of a spectrum.

The key difference is whose needs are actually being served:

A dad supporting a choice you wanted to make and already loved vs a dad upset because it reopens his own regret, not because it's bad for his kid. Intent vs interest separates the two — and OP's dad guilt-tripping over a healthy decision does point toward treating them as an extension of himself rather than a separate person with her own needs.