So, in the subject of "what has mysteriously changed today in S22" I suddenly find I cannot right-click the timeline "ruler" to get the menu that allows me to choose specific amount of timeline display - or show entire project.
I right-click and nothing happens. All other right-click menus are working and I can still change the timeline size; by dragging the positioning slider at the very bottom or by using numpad minus and plus.
I've reloaded, I've rebooted. I've tried different projects and I've started a new project. Still no right-click to change timeline size or select "entire movie". It worked when I went to bed last night... maybe it doesn't like Wednesdays.