Using HA Green and it’s been working well but I would like to change my ISP from Xfinity to Ziply and upgrade my router in the process (currently on Xfinity’s router). I’m a quick learner and have been able to do a lot with HA, but even things labeled as “HA for beginners” feel like half the content goes over my head still, so really appreciate what may feel like overly simplified explanations and not assuming base knowledge in replies. From the digging I’ve done through the threads on new routers, what I need to do is set up my new router to have the same IP, SSID, password, and settings before connecting anything to it, does that sound correct? I’m primarily running TP-Link lights, plugs, and motion sensors. Also integrated with my Reolink cameras and their hub. Also my cat’s litter robot and my Roborock vacuum. Thanks in advance for your patience since I feel I am likely to have questions. 
The best practice is to have your own router that connects to the ISP router and then you don’t car at all what that router is connected to and your stuff stays stable.
All you WIFI and ethernet and all that would stay the same.
That is my suggestion.
This makes sense to me and I love the simplicity of the suggestion. The problem here is that the current ISP router that my HA is connected to is an Xfinity router that I will have to return once I switch to another ISP so the router change will be necessary anyway.
The good thing though is you can pick up a router and change it out right now, then never have to do it again.
I believe the best practice is that you don’t use anything from the ISP including their modem/router? I currently use xfinity and have a Surfboard modem and Unifi Ultra Cloud Gateway for a router. Technically, your Xfinity device is probably a modem and router and what Ziply would provide is also.
I have never heard of Ziply but, if you can use your own modem instead of renting their combo unit, i highly recommend that. Then get your own router.
I just stick a router in front of whatever they supply for free. Yes it is a double NAT but I have never seen any ill-effects from that, honestly. It’s worked for me with 4 different ISP’s so far.
My routers WAN just plugs into their port. They may have a WIFI, I just ignore that.
Xfinity doesn’t provide their modem for free. If I remember correctly it’s $15 a month but they make no effort to tell you you don’t have to use their equipment.
Appreciate all the info. I will be getting my own router when I make the switch but the question I actually have at the moment is about the switch a new router with HA. Am I correct that what I will need to do is set up the new router to match the IP, SSID, settings, etc, of the old to make the transition more seamless?
That is possible, yes. All the settings match and it should just work.
Thank you! This is helpful to hear and now I’ve also got lots of good info on how to manage the setup going forward!
A bit of upfront planning like you are doing is to be commended.
Documenting all your devices into a spreadsheet for reference is convenient.
Investigate your current router DHCP settings, trying to allocate a static IP to each device on your LAN, and then do the same with your new router. This will make troubleshooting any possible problems far easier.
If you do this well, you should be able to simply swap the two routers and everything should just work. Be sure to only have one connected at the same time to prevent clashes.
The alternate suggested earlier, to have both routers involves ensuring only one allocates network addresses and has unique WiFi SSIDs.
Regardless, keep your old router for a few days before returning it in case you need to swap back to check a setting you may have overlooked.
The dream of being able to export your router network configuration from one manufacturer and directly import it to another is still far off. Having the speadsheet will help with organisation and cut-n-paste to prevent typos.
Thank you! Love a spreadsheet so I will implement this. The plan at this point is to configure the new router to match the Xfinity gateway and create the DHCP reservations, switch the Xfinity gateway to bridge mode, then connect the new router and ensure things are running smoothly before finally pulling the trigger on the ISP switch which should then be seamless.
Really appreciate everyone’s responses!