Been fighting this battle literally for years.  Back when Spectrum was Time-Warner we had this same problem.  There seems to be a bad node / Router that one technician told me was working with two of its four channels broken.  it seems to not be a terrible problem unless lots of people (in my neighborhood?) are using the internet.  Problem is today, everyone is using the internet, all day.  I keep getting the run around, with a new modem, a booster in my garage, promises that it has been fixed.  Below is an MTR trace from today.  You don’t even have to be a techie to see something wrong and see where it is.  The Spectrum Man is coming again at 4pm.  Have a whole document to hand him this time.  Next stop, FCC …

$ mtr -c 10 --report google.com
Start: 2020-07-30T14:05:56-0500
HOST: pi4ubuntu                   Loss%   Snt   Last   Avg  Best  Wrst StDev
  1.|-- _gateway                   0.0%    10   28.7   5.8   1.4  28.7   8.3
  2.|-- cpe-66-68-128-1.austin.re  0.0%    10   12.7  16.6  10.0  24.8   5.3
  3.|-- tge0-0-5.ausutxla01h.texa 10.0%    10  4501. 4356. 3782. 4718. 287.3
  4.|-- agg50.ausutxla01r.texas.r  0.0%    10   17.0  17.4  11.5  33.9   6.8
  5.|-- agg22.dllatxl301r.texas.r  0.0%    10   40.2  30.2  15.4  44.3   9.2
  6.|-- bu-ether24.dllstx976iw-bc  0.0%    10   21.4  24.9  16.6  41.1   7.1
  7.|-- 72.14.218.12               0.0%    10   52.9  24.0  18.0  52.9  10.3
  8.|-- 108.170.229.24             0.0%    10   42.0  29.1  18.4  49.5   9.3
  9.|-- 209.85.244.59              0.0%    10   21.9  25.8  20.8  35.6   5.0
 10.|-- dfw28s23-in-f14.1e100.net  0.0%    10   23.3  20.9  16.9  27.6   3.5