I have one, and modulo a slightly unexpected presentation into my Android device, it does exactly what it says on the label.

My Phone is an older Moto G30 model which predates "eSIM by default". It does not run current Android, it's on 12.

The unexpected presentation is that it shows up by default as "engineering test SIM" or some other text. This can be changed on my phone.

The JMP utility works fine with Q/R codes, and I successfully used it in the US, Republic of Ireland and the UK. The UK provider mappings were a bit meh with Airalo but another eSIM provider worked fine, and I was able to jump between configurations (modulo a reboot, which it clearly warns can be necessary)

10/10 would use again. will. I fully expect to use this in place of locally bought travel sim in 2025 whenever possible. I travel for work, I depend on my phone for 2FA and other functions, and I prefer not to have to open it up and manually configure sims if I can avoid it.

I can't think of a single problem I sheet home to the JMP adapter, other than "reboot required" which frankly could be me, or Android 12. eSIM activation is fiddly, there are nuances to how you configure data. It seems to need roaming enabled. Bizarre!