What I did was "Clear browsing data" from the settings and selected everything/all-time. I also went into the dev-tools and deleted every indexedb and cache and localstorage item.
I also deleted Construct from chrome://apps. Still won't open ANY project (including examples)!
Within a private tab I can open example projects but I use the VScode add-on in many of my projects... After installing this add-on and refreshing the page I can no longer open ANY projects again. This same behavior occurred in the Opera browser. This same behavior occurred in the Edge browser.
The problem with Firefox & Brave is that it doesn't give the option to open a project folder...most of my projects are saved this way. IE won't run Construct (pushes to Edge.)