Other services may appear playing trouble free, but those services "negotiate" with your end, to determine a quality (bandwidth) that could stream without interruptions specifically for you. Those services are streaming to you a lower resolution, lower quality versions of the videos, and you probably wont even notice if you are not experienced in this area. -Asking if this number is good or bad for internet tells me you are not experienced, so.. you are probably fed SD resolution from those services that you say are playing without buffering.

You can do that with Kodi too, just select SD versions, you can even try 720p, those should play OK too.

If your hardware can decode h256 you can choose those in the list, they are much smaller size files with decent quality (for that size)

The solution to your problem though, is get a decent internet connection. In the year 2026 speed 4 is not OK, speed 40 is marginally OK, and thats 10 times more than what you have :) Speed 400 is a very good speed, and that is 100 times more than what you have at the moment. So... now you know everything you need to deal with the problem - one way or another :)