Unable to connect to internet. Xfinity has done all they can. Ive tried everything. Not connected

Well, if you’ve tried everything, then there is nothing left. 😀

However, it might be better to list specific things tried and specific error messages and behaviors you have seen.

The model number of the Roku might help, as might information of the band(s) you are using.  (For example, Xinity has been known to send gateway updates that turn off the 2.4GHz band.  But some devices, including some Rokus, only use the 2.4GHz band.  Xfinity did that to my parents, and the tech support call I got was that mom's printer quit.)