> none of the carriers here in Europe that do prepay offer eSIM anyway.

Not true, e.g. in Portugal: https://www.nos.pt/movel/esim (though you need to go to a store to pick-up the QR code, I think to avoid people from other countries using it?), https://www.meo.pt/servicos/movel/tarifarios-telemovel/e-sim same thing