OK, what kind of connection are you on and in what country?
Personally, I would use the DSLreports test which shows a bit more of an accurate set of data and I would simply run a couple of tests per night over several days.
I've had some variable issues with my provider over the last 6-12 months, we are on FTTC so not really a neighbour issue, definitely the ISP. To be able to monitor this, I set up Telegraf (which outputs data to InfluxDB) to regularly ping a number of different known IP addresses and to test connections to most of the common DNS services. I can then review the data in Grafana. The other day we had a short outage on our service - 10 minutes - and I could monitor exactly when that occurred. Previously, what I thought were outages were actually Google DNS dropping out periodically so the monitors let me know that and switch to a better DNS.
In your case, the ping tests will likely start to show failed pings and increased ping-time. Checking multiple addresses for well known endpoints will let you see if your ISP has restricted bandwidth to a particular popular service - Netflix or Youtube for example - which is not unheard of, especially, I believe in the USA.
I realise that none of this relates directly to Node-RED. But though NR is great, it isn't the answer to everything! Shocking I know!