Would an Arris Touchstone SB6183 work?

... SB6183 ... Download speeds up to 200 Mbps; Upload speeds up to 100 Mbps ...

The SB6183 is approved for use with plan speeds "Up to 373 Mbps" (see the "All Compatible Devices" link near the bottom of https://www.xfinity.com/support/devices). But you won't get 100 Mbps upstream, that's only available in certain locations with one of the newer Comcast rental gateways, or just 4 retail devices:

• Hitron Technologies:
•     CODA       934 Mbps / 456 Mbps
•     CODA56   2.33 Gbps / 455 Mbps
• Netgear:
•     CM2050v 2.32 Gbps / 455 Mbps
• ARRIS / Surfboard:
•     G54          2.34 Gbps / 474 Mbps

Also see https://www.reddit.com/r/Comcast_Xfinity/wiki/knowledgebase/next-generation-internet/

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@user_5tipgj

Hey there! Please visit this link to find out more details about our approved modems, as these do vary per speed and market. https://www.xfinity.com/support/devices/