Best Way to Extend FIOS Network Without Impacting Roamio and Minis

Hoping that someone more network-savvy than me can help here. Current setup is FIOS 75/75 using Quantum router connected via coax. I have one Roamio and two Minis, all connected wirelessly since none are near the router. They all work fairly well, so that is not my issue. The issue is that I have dead spots elsewhere in the house (particularly with the 5GHz network) so I was hoping to somehow extend the network to provide better internet access to these spots. I have an Airport Extreme collecting dust that I would like to use but I would be willing to buy something else if necessary. Something like the Luma (or more expensive Eero) piques my interest but I'm not sure if this is compatible with my current setup or if it will maybe break the MoCA connection that currently allows my Minis to connect wirelessly. (I've probably butchered some of the terminology here but hopefully the gist of what I'm trying to do and what my concerns are is understandable.) I welcome any and all suggestions.