Thank you for sharing your experience and suggestions.
My interest started because I didn't know that I can have two eSIMs on at the same time. Then I realised that some of these adapters can have up to 50 profiles/eSIMs and therefore I could easily move eSIMs from device to device.
However, the latest interest is fuelled by Amazon. I was searching where I could get any of the cards in the UK and Amazon claims that they have an IMEI serial number! I expect that they are wrong and confusing IMEI with EID serial number, which is a unique 32‑digit serial number assigned to a device’s eSIM chip. But it would be awesome if the cards actually have IMEI... if nothing else because some network providers lock eSIM to specific IMEI.