Privacy recommendations for ISP Gateways

So until now I’ve used my own modems and routers. However, the one that Xfinity (Comcast) offers is currently free as well as allowing for unlimited data usage (as opposed to someone using their own). I have a lot of people using internet now, so it makes sense to go with that one.

Best recommendations for privatizing things when using the ISP’s modem/router? (I do use VPNs on my devices.)