It depends a bit on your use case.
If you haven’t written a custom weights_init method, but just initialize the model and thus use the default random initializations, I would recommend to just recreate the model.
Note that you should also recreate the optimizer in this case.
On the other hand, if you already defined a custom weights_init method, just reset the model via model.apply(weights_init).
Also, not sure if this fits your use case, but you could initialize the model once, create a copy.deepcopy of its state_dict, and reload this state_dict for each fold via model.load_state_dict(state_dict).
Let me know, if one of these approaches would work.