Firefox, and I think other browsers too, open links in a new tab when holding Ctrl while clicking. On monday.com some links overrule this normal behavior of the browser and open the link in the current window.
Some often used links where this happens are the links in the list of boards and the links to show the details of an item in the spreadsheet.
I think it would be better to restore the normal browser behavior, so a link works like it does on any other site.