My strategy paid off. Now with the 4 cancelled flights to/from Poland in June.

The cancellation emails from Ryanair states:

We are allowing customers to change their cancelled flight to another date or time on the original route or to any other route within our network. You can move your flight to any date within 14 days before or after your cancelled flight.

This means that even pure date changes (same route/flight) will also have to be within +/- 14 days? I'm not sure if this is in line with the applicable EU regulation.

Obviously, for the generous offer to rebook to any route within the FR network can be limited to 14 days before or after the original flight.