After a year of my phones (Note9) connection and speed being abysmal for anything beyond a few seconds of use, i finally found a trend. You should be able to notice it in the screenshot.
Mind you, between all of those tests it disconnected multiple times as well, despite showing 4G and two bars.
I made a thread a long time ago where i couldn't use my data at all which turned out to be a tower issue, however i am currently regretting paying for this phone for i can barely use the data as the issue still exists just in a lesser extent.
To break down the image, essentially if i engage in anything strenuous that requires a notable amount of bandwidth or download/upload speed it lags out. If i watch youtube it lags out, if i watch twitch it lags out, if tether to my PC it lags out. It will work for around a minute to begin with, working perfectly at say 1080P on youtube then it will auto readjust to 240P and buffer every few seconds.
This never ceases to fail. I have 50GB's of data that i pay for with the intention of USB tethering when my ADSL2+ isn't performing too well (which is pretty regular) but i haven't even been getting through 4GB of data due to the frustration of it. As soon as i decided to do something i also get massive latency spikes, upwards of 20000ms. I've tried to find the issue countless times but i really don't know what i am doing when it comes to internet and networking so i haven't had any success.
It isn't a current or acute issue with my address, for pretty much the entire year it has been doing the same thing and the map hasn't shown any tower outages bar once and the coverage is great for 4G.
It could be an issue with my device however it was doing this from day one, i don't really know how to isolate that.
How do i approach this? I am honestly lost as to what to do, i feel like i've wasted a ton of money on something i can't even use which is really dissapointing.
It has been my experience that a low signal really does have a dramatic affect on speeds. For some reason it does not seem to impact mobile broadband devices as badly. I would be trying that sim in another phone to see if the results are the same.
Does the same condition occur when the Bluetooth pen or any previous connected Bluetooth external speaker is disabled. Wouldn't usually expect a clash on such a modern unit as co-existance has improved over recent times, but one never knows. I assume your Android firmware is up to date - have you done a soft reset on the Note 9 and flushed out the Browser Cache Data and History in case there are any corruptions there?