I do not use tags, because the fonts are big and break the continuity of the list. I do not use note text for the same reason (I could set the preview to zero lines, but that's overkill).
To complete a task, I just delete it.
I know people have suggested better ways using tags (example tagging it as 'done'), but for that I'd either want to hide the tags from the display in the list, or make the font tiny. I don't see a way to change the font size for the tags.
I'd like to keep completed tasks for posterity

Thanks