Browser starts at the startup

That was worth a try. An upgrade/repair install is a powerful tool that fixed me once. I'm glad matters got no worse. For less anxiety, make a Windows system image backup before doing anything big. Want instructions?

But I think Windows just one way or another wants modules to be loaded & ready for use even after the program that uses them is closed. It's meant to speed things up in case you open it again. And there's prefetch as well as you suspected. So, it's a feature -- & an upgrade/repair install cannot "cure" a feature.

did an inplace upgrade right now and still doesn't seems to fix the problem.

I am doing an in place upgrade now, and in the comments of the tutorial I was watching, one guy said that after doing an in place upgrade, they were not able to check for upgrades and upgrade their PCs from settings

Can you spot it in Autoruns? I still say, it has to be in Autoruns or it isn't a startup issue. Chrome must do it after the boot, then, after you click it to run. After you close Chrome, the stuff sticks around a bit to be there just in case you open Chrome again. It likely would unload as soon as the RAM is needed by something else.

Or, maybe you're right that prefetch is at fault. That article I found says how to temporarily turn it off to see.

I don't think it is at fault. I just reinstalled chrome, and now again chrome is doing the same thing ;-;