In blank doc I create a guide, then can't remove/highlight/move the individual guide.
View > Lock Guides is "off"
Trying to determine if Photoshop thinks it's a Canvas Guide (even though I drag created guide), I go to View > Show > Guides or Canvas Guides,
guides hide in both situations. Similarly I can Clear all guides using either Clear Guides or Clear Canvas Guides.
Show/Clear guides and show/clear canvas guides will do the same thing unless you are using Artboards. If you are using Artboards then you will see an additional option to Show/Clear Artboard guides. That separates the Artboard guides from the Canvas guides.
To move a guide, provided it is not locked, either select the move tool and drag or hold Ctrl (Cmd on Mac) and drag
DOH... was using Selection tool, not Move tool (nefariously hidden from me by the artboard tool!... UI challenged at times even after 29 yrs :/ ) TX
... UI challenged at times ...
Aren't we all !