Hey @donkeykong9000,
project DEAL is an initiative from Germany, so for now, only Germany. The Netherlands already negotiated something alike, although they did not get a very good deal, the publishers used loopholes to give them less than they thought they paid for! Finland is in preparation of a similar project and I think all other European countries are watching. Even more important for DEAL to achieve their goals, hopefully this will make the work of the others easier!
For the pressure aspect, I think Germany wields a decent amount of power. With a certain influence on other European countries, this could easily evolve into an European boycott... But this is speculation! ;)