Each speed test will not get the same results. Remember you are repeating what others have asked about for many years.
Again, it won't match because of what paths the tests took as well as internet traffic at the time.
I do a test on cnet speed test and I see just under 15mbps but on Verizon speed test I see 24mbps. I reset my router and cnet showed a speed of 24 mbps and Verizon speed test showed 48mbps. Why the difference? So then I tried att speed test and got download of 26 and upload of 34. So I tried charter speed test and got 35 download and 40 upload.