Depends. The latter in case of English pronunciation.
Whereas in case of original German pronunciation, "do-all" in my view wouldn't quite fit. I.e., the "do" as in the English verb "(to) do" for the "Du" part would work, but next would be a dark, somewhat elongated "a" as in the English word "father" (or the German "Vater"), followed by an "l".
If you want to hear it pronounced several times by a couple of Germans (also including Dualfred (*)), you could watch this recent video:
Greetings from Munich!
Manfred / lini
*) With him pronouncing "Dual" in a somewhat more Bavarian way.