Look at your SNR - down at -1 on the first set which means from sync to stats it dropped around 6dB and only just holding 2400 ... Then on the second 10dB and 4200 again a 4dB improvement in te few moments from sync to stats.
My first checks would be to try and find out if there is a large variable noise source somewhere that is causing interference. It could be in your house, a generator down the street ... Turn off everything
in the house and just run the router and PC - but it could also be the PSU for one of those - however you say that you changed modems at one time, but was the Huawei power supply still plugged in?
M H C
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