Diane Frankel wrote:

It has been my experience in doing my family's research that the
Americanized version of Tewel/Tuvia
is none other than David. Go figure.!

Not quite.

Tevl an Tuvia are distinct names.

Tevl (however spelt) is used in Yiddish as a kinui for the Hebrew
David - hence Dovid Tevl.

Tuvia is a corruption of the hebrew name Tovia.

The names amy have been used interchangeably in more recent generations.

Perets Mett, London
searching METT (Warsaw), GRINBERG/HOCHMAN/WINER (Klimontow), GINSBERG
(Staszow), GLATT (Ulanow), JOACHIMSMANN (Berlin), PEARLMAN (Verzbelow),
MALKUS (?), MERSKY (Molchad), RABINOVICH (Romanovo/Mohilyev), MACCOBY (?)