I think higher tier beacons don't work as intended. In the previous version of the mod (for the factorio 1.0) they accepted higher tier modules and the area of effect changed by beacon tier. None of these are working now, except that higher tier beacons have more slots. Cheers!

All beacons have always accepted all tiers of modules
That part hasn't changed.

Higher tier beacons now have more module slots rather than more range, yes. This is working as intended.

But now they dont accept them. Neither productivity mk5 nor god productivity.

Correct. Productivity in beacons is stupidly over powered. As I said, the changes are intended :-)