Notebook Wireless and Networking

Hello, I've been having several issues with my wifi adapter.

First of all I'm getting disconnected from Internet several times a day ever since I bought this laptop. When I diagnose my network connection I get the message "default gateway is not available : Solved" and that fixes it temporarly, but it doesn't prevent future disconnections. It's sometimes very annoying, I already experienced getting disconnected twice whithin a 5min gap. I'm only experiencing such a thing with this laptop, I'm not getting disconnected on other devices.

The second problem I'm getting is quite recent. I've only been using 5ghz wifi ac, and I was getting 300Mb (download)/200Mb (upload) internet speed consistently for months. I'm still getting the same speed with my phone/second laptop. However, since I got disconnected from the Internet again yesterday, I tried using windows diagnostic tool as always to restore the connection but the PC lagged out and I got a BSOD. After it restarted I felt like the internet speed was reduced, and indeed when I tested it out I've only been getting 80download/4upload since then on this laptop. Ethernet speed is still the same aswell as WIFI speed on other devices. The upload speed is the real issue, I could do with the 80Mb/s download speed even though I was getting 300Mb/s a few days ago. I thought it might've switched to the 2.4ghz frequency but it says that it's connected to 5ghz in VHT mode. I've tried using different drivers to no avail. The one I'm currently using is the latest (dating from Feb 2020). It's more and more becoming a nightmare to get the WIFI working correctly on this model. I also wanted to add that I'm using the Bluetooth regularly so I haven't tried disabling it (I saw a few people advising to do it), I can't afford to do so. Also, BIOS is up to date. Appreciate a solution please