Netflix has a good internet connection test website and they will tell you what quality video streams at what internet connection rate. I don't need to check either to tell you that your pipe is good for 4K via Netflix, maybe even 8K video. 10 Mbps is good for 1080p HDTV, 5 Mbps is good for 720p HDTV. All of those guidelines allow for some wiggle room without harming the video stream. So something must be going on with your connection; 60 Mbps is enough to run a server.
go to: www fast dotcom
... to access Netflix's Speed Test.
NEVER trust your ISP's speed test; they can give your pipe priority during the test to give unrealistically high throughput.
I will give you an example:
I have a 10 Mbps down / 960 Mbps up pipe.
While streaming NFL Network and an NFL preseason game (Houston vs Kansas City, Week 1) on my TV at 1080p over the internet (ROKU), typing this post via my browser and with my mail app running and checking for mail every 5 minutes, I get 7 Mbps down 800 Mbps up via that test going from my home in Canada to Seattle WA and back (about 2400 miles round trip). If I turned everything off except my browser and the test I will get a bit more than my paid-for speeds.
Your pipe is (supposed to be) SIX TIMES fatter than mine.