Anything that gets “in between” your browser and the internet has to be suspect. That will include any extensions (in Chrome, it’s Spanner – Settings – Extensions) you’ve installed plus any AV. If you’ve installed multiple AV over the years, remnants of them might still be interfering and, indeed, tripping over each other.
As always, a clean install of the OS and Apps will tend to sort these out but it’s a step you might not want to take.
Why don’t they always work? It’s because no one else will have installed/uninstalled/modified/updated their system exactly the way that you have over the years. When I worked in IT and we were dealing with thousands of systems, the #1 goal was that they were all maintained exactly the same. That meant we had a very good chance of any tested changes working on all of them.