C6250 Internet LED blinking, connection spotty despite strong signals

C6250-100NAS

Firmware V1.01.29

Provider: Consolidated Smart Systems (apartment building)

we have 3 devices connected wirelessly and 1 connected direct (a tv)

My wireless internet has been spotty for many weeks to months - mainly the upstream. I mostly notice it while on Zoom calls with choppy voice / video. For the most part i don't get fully disconnected, just choppy coverage and bad network notifications despite speed test telling me i have strong connection. My average is 60+ Mbss download and 12-26Mbps upload. 

I live in an apartment building so there could be some line issues.  However my TV is hard wired with ethernet and I don't seem to have any issues with it. Also this connection rarely TOTALLY drops, it just spits a bit making calls unbearable.  

I called the ISP and they said their connection is great. Since my 90 day router warranty has expired they want to send a person out for $100. Before I do that i wanted to check all from the modem side.  The modem is about 1 year old. 

Diagnostics I've done:

1) i power cycled the modem. Fixed for a few days but the problem came back.  

2) I reset the modem following instructions in Genie. Fixed for a day but the problem is here again today. 

3) I checked my connections - the white cable plug is physically close to the router and there are no splitters / amps attached. I have unplugged and replugged this in, inspecting the cable. (part of me wonders if the cable wire may be the tiniest bit bent). 

4) i looked at Genie's cable connections and have attached a screen shot (the power fluctates between 7.3 and 8.7). i have no "uncorrectebles" and some "correctables" this seems to start from zero every time you reset modem. 

5) I physically inspected the modem - staring at the screen the 2.4hz, 5hz and the far right one (3 prongs) are sort of blinking green. They are on, but not 100% solid. They strobe a bit.  This is true despite my troubleshooting. Not sure if this is meaningful or not...???

Any recommendations? thanks so much in advance! 

wendy