I did not read this proposal, but if it is meant to pass as an EU directive, it will then require the member states to ratify it as an actual law, following the general principles contained in the directive. So for example, if the EU directive that passes says "The amount of the UBI has to be between 50% and 80% the average salary", the countries can set a number that way, which can be revised or not in the future, etc. That's how it usually works, for example PSD2, about payment services, had general ideas that obviously member states implemented differently in the details.

In theory, if a member state implements a directive in a way that is not faithful, it might risk a fine from the EU, but member states generally do not care much about it, I am not even sure if all of the fines that have been issued in the past have been paid...