When you troubleshoot, if you don't know what is wrong, you can take the route of eliminating other things to narrow down the possibilities. If you put your computer on a wired connection, you would establish the system is capable of preforming the way you want. You may have some malware running in the background causing problems or something else. I can't tell you how to put your system on your wired network, but you or a friend should know.
If the system runs OK on a wired connection, then you know for sure it involves your wireless connection or some component of it.
But once you find a place when the system operates as expected, you can then build back up to where it starts having problems, then you know what is wrong. Repairing the problem is the next step.
And information helps. One of my suggestions would have yielded the info below. One is for a 2.4 G connection and one for a 5 G connection.