My wifi connection is much slower on my Lenovo IdeaPad than on my phone (How to fix it?)

Hello 👋. About 2-3 weeks ago, i've first noticed that i'm having wifi connection issues: websites were loading quite long, games were lagging, etc. Until those 3 weeks ago, i didn't have any connection issues at all. Before the issues started, i was able to reach 100-150 mb/s of download, and about 80-100 mb/s of upload, both on that mentioned notebook. With this speed, everything was running correctly and quickly, and then one day i wake up, and i notice that websites take long to load, so i run a speed test, and turns out my wifi speed dropped significantly. I restarted the notebook, but it didn't change anything. I tried turning off wifi connection on my notebook, restarted it, and turned it back on, still with no results. And because i have Avast installed on my notebook, i decided to run a test and clear up any unnecessary stuff. I also updated everything that could be updated, from windows itself to separate drivers. After everything was updated, i tried restarting the notebook once again. No result. Since then, i've read many articles from (this) microsoft support website, reddit, and other websites where i could potentionally find help. I tried restarting, turning off and on the notebook many times, and eventually, i gave up, because none of the ''solutions'' worked. Yesterday, i returned from Germany, where i was on a short vacation. I took my notebook with me in hope that connecting to a different wifi might fix it. I was wrong. I couldn't even connect to the wifi on my notebook, even though it worked fined on my phone. Now that i'm back home, i tried reading more articles on other websites, and watched about 30 videos that had solutions that apparently should have fixed my issue, but they didn't. Then i came across 2 youtube videos, where i am supposed to use the command prompt. I watched those 2 videos, and tried all methods that used the command prompt. I entered the command that i was supposed to, restarted the notebook, and then i ran the speed test again, and got 102 mb/s of download and 80mb/s of upload. Then after about 5-6 minutes, it changed back to 5mb/s (download) and 60 mb/s (upload), which is the average speed that i have since the issues started. I tried checking if there are any windows updates or drivers to be updated. (there were none) I tried reinstalling the wifi adapters many times, restarted the notebook many times, and then i decided to uninstall some apps. I uninstalled few games, the VPN, and some other apps that i wasn't using, and then i restarted the computer again. Still no results.

Between when the connection was working fine and when the issues started, i didn't install or uninstall anything, and i didn't update anything. (I was at vacation at that time, and i didn't have my notebook with me, so i couldn't even do anything on it.), and when i returned from my vacation and turned on my notebook, all of a sudden the connection was much slower. I already mentioned the connection speed i had before the issues, and after the issues started, but i didn't mention that the wifi connection was perfectly fine on my phone. While i got 100-150mb/s of download on my notebook, i got 170-200 on my phone, and when i had 80-100mb/s of upload on my notebook, i had 130-150mb/s on my phone, and all of this was measured in the same room. I literally have the router like 2 meters from the place where i measured the speed, plus the router was in the same room, so the issue must be in the notebook itself. For those that understand computers well and could help, here is some info about the notebook's system specs.

Lenovo IdeaPad C340-14API
CPU: AMD Ryzen 3 3200U

GPU: AMD Radeon Vega 3 Graphics

Windows version: Windows 11 Home ''23H2''

Yes, the notebook is a bit older, but usually, it works fine. I hope someone has a solution/tip on how to fix my issue.

Thomas