Hitron CODA56 cable modem stuck on legacy DOCSIS 3.0 profile/bootfile

I just replaced old (customer-owned) CM500V DOCSIS 3.0 cable modem with new (customer-owned) Hitron CODA56 DOCSIS 3.1 modem, under Xfinity 1Gbps down/100mbps up plan.  New modem is activated and providing internet access, but speeds are same as old DOCSIS 3.0 (getting about 300mbps down/9mbps up).  I suspect new modem did not receive correct DOCSIS 3.1 provisioning and is not locking on to DOCSIS 3.1 download and upload channels thus is not delivering expected speed (CODA56 is certified by Xfinity for 1Gbps and above performance).  I reached to frontline Xfinity tech support (twice) and they insist that DOCSIS 3.1 config *has* been pushed to my modem (they confirm that correct CM MAC is bound to my account).  But various AI bots state that if wrong provisioning file is pushed initially, Xfinity's automated provisioning system may not be able to "clear its cache" to correct the problem, and often requires manual access to CMTS to manually clear the incorrect provisioning profile from customer's account profile, input the explicit CM MAC, and hard-push the correct configuration file directly over the line.  The AI bots recommend working directly with Digital Care Team (corporate official employees based in U.S.) via Direct Message in these forums to get help to resolve the trouble.  I am hoping someone from that team can DM me to work with me to resolve this problem.  (Existing ticket [Edited: "Personal Information"] was opened by frontline customer support.)