My PC freezes (or extrmmely slow) after about five minutes of use but the mouse moves

After about 5 minutes of use, like browsing the internet, the PC freezes or extremely slows that it is no different from freezing. If I hover my mouse over the taskbar in this state, the mouse icon turns into a "loading wheel". However, doing nothing or running cmd just after booting my PC don't seem to cause the problem.

I ran the Windows Defender scan and found no malware or virus. I updated my Nvidia driver. I suspected the thermal problem of my CPU, so I used Core Temp, and it seems normal (80c). I suspected my RAM failing, so I ran the Memory Diagnostics, but it didn't spot a problem. I suspected my SSD failing, so I used Crystal DiskInfo, but it was shown healthy (93%).

I then used the popular DISM solutions through cmd, and it did spot a repairable problem. I got a DISM error 0x800f0915 during RestoreHealth but figured out a solution, and I eventually repaired. I then ran sfc /scannow. Bad sectors got repaired, and cmd detects no problem... yet the same freezing problem persists.

Now I have no idea. What's going on? I'm not even sure if it's a software problem or hardware problem at this point.

Is it dust? Should I clean the inside of my PC? Is it one of my HDDs (E drive) since its health is shown to be "Cautious" on Crystal DiskInfo? But it has been "cautious" for months and has caused no freeze or slowdown until a few days ago. Is that HDD the problem? Should I disconnect it? Or is it something else?