The S33 is a great DOCSIS 3.1 modem with a 2.5Gb port, but it's more than you need for 500Mb. It's a good way to go for futureproofing though. FYI, I'm using an S33 on a 500Mb connection right now.

Amazon currently has a package with the S33 and Arris W121 mesh package for $409. https://www.amazon.com/gp/product/B08TL6NMV9/ I have no idea how good the W121 is, but having two APs will cover more area than a single unit, if you've got a bigger house.

I'm partial to Asus routers. Amazon currently has the GT-AX6000 for $258. It has 2.5Gb WAN and LAN ports, so you could get >1Gb internet through the router and to client devices. It's supported by Merlin as well. With $155 for the S33, you're only a few bucks over $400.