I understand your problem with pasting pure unformatted text. This may be more work than you like (we can try to automate that later) but when I paste data from Notepad, I am prompted with an import screen as you can see below. Select the column header(s) and then select Column type: Text. This should solve your paste/import problem. An alternative is to handle this with an AutoHotKey script.
Oh b.t.w. the @ is the format type for text, just like you have HH for 24 hour or ddd for weekdays...
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…