Something different - do an Ookla speed test and check your download latency (see below circled in red). I have 500/500 internet speed on fiber and my download latency is 7ms. I’ve seen others that had over 300Mbps download speed but over 500ms (half a sec) download latency. That much latency is probably going to cause a few stutters…
Edit: Great article regarding latency and oolka: Introducing a Better Measure of Latency | Ookla®
