Mistake to change from Spectrum (Coaxial) to Fios (Fiber optical)???

Hello

I changed from Spectrum to Verizon Fios today, my sound is now terrible, everything is missing including the bass.
My Martin Logan Montis lack bass and poor stage, 2nd system with Raidho speakers is far worse.

Spectrum using a coaxial cable from street pole to modem, Fios using optical.

Have I made a mistake? Are there any solutions or do I need to change back to Spectrum using coaxial?

Thanks for your input.