Denon AVR-S770H: 75 watts or 110? Both, and the difference is 1.6 dB
Yes. The AVR-S770H into the Bronze 50 7G stays inside the amplifier's impedance rating. At 3.5 m the pair reaches about 99.9 dB in a typical room.
The Denon AVR-S770H is a fair match for the Monitor Audio Bronze 50 7G. The nominal impedance is inside the amplifier's rating, which is the condition that matters.
At 3.5 m in a typical room, the stereo pair reaches about 99.9 dB. The second speaker and the room each contribute roughly 3 dB, which is the usual allowance for home listening. That sits 5.1 dB under a 105 dB theatrical peak, so loud film moments are where an amplifier with more voltage starts to matter.
Behind that level: the AVR-S770H is rated 75 W into 8 Ω, and the Bronze 50 7G works out to about 86.0 dB for 1 W at 1 m from the sensitivity the maker actually published. Nominal impedance is 8 Ω.
The published minimum impedance is 4.0 Ω.
An amplifier rated above the speaker is not automatically dangerous. Clipping from too little power is what sends extra energy into the tweeter. Keep the volume clean, and treat an unpublished impedance dip as unknown rather than as a guessed fraction of the nominal.