1 Gig poor performance

I am a Comcast employee. I have the 1 Gig service. I seldom get above 500 Mb and avg about 150 to 200 Mb. I have the latest Comcast modem, with an Orbi wireless router attached to it.

I also have 3 IP TV boxes as well. I cannot put the Comcast router in Bridge mode or I lose my IP TV boxes. I have even turned of the ORBI router and still the wireless gets the same speeds. I have had a tech out twice and they couldn't find anything wrong with the cabeling.

I look for your expertiese to increase my bandwidth speeds and fix the performance fluctuation.