Ask HN: How to Fix Unstable and Slow wifi on Linux Mint?

Hi there. I have a pretty old HP laptop which is running Linux Mint currently. When joining the home wifi network is quite slow. I went through similar issues on some random linux (also mint) forums and tried everything. It got a bit better after disabling features like PowerManagement and Ipv6. However, still I cannot get more than 15 download speed while from the same distance my other device shows 60-70.

Question: As a last shoot I decided to either upgrade physical network interface card or easier to buy a usb wifi network adapter and use it. Do you guys thing it would help me to solve issue ? Buying physical network interface card might be tricky as I am not sure which spec should be to "fit". Thanks.

Note: Os kernel is up to date, no solution there.