I have a small router from GL iNet, I really like it. It is not one that uses a SIM card though, but I don't usually travel to places that don't have wifi. I have my VPN installed on it and so I just plug my pocket router into the hotel or airbnb router and then all my devices already know my wifi connection and all traffic goes through VPN.

I imagine their products that support the esim would be equally as good.