Is it normal that the Thai Pass system did not ask for my visa when applying for a COE?

Did you get email confirmation?

In theory the visa you are going to enter on IS irrelevant. The ThailandPass system is in place to ensure you are either vaccinated or not and depending on which case whether you have to right hotel bookings and insurance for your intended entry point.

It’s up to the immigration officer to allow you how many days on arrival you get depending on the visa (or exempt) entry you are using.

From seeing reports from others it seems that what visa you are entering on is irrelevant to the ThailandPass system. It’s still all new so we may have to wait a bit to confirm stuff, but it does appear to be the case.