Set file created/modified timestamp to the earlier of the 2 for a ton of files?
The example shell script code, show below, uses GetFileInfo and SetFile from Command Line Tools for Xcode, which the latter is needed to change the creation date, as touch can only change the access and modification times.
If you do not have Xcode installed, then just install the Command Line Tools for Xcode...
In Terminal: xcode-select --install
After installing Command Line Tools for Xcode, then in Automator you can create a workflow or Service/Quick Action with the appropriate actions to pass the target files to a Run Shell Script action with settings Shell: [/bin/bash] and Pass input: [as arguments] using the following example shell script code:
for f in &quot;$@&quot;; do

    [ -f &quot;$f&quot; ] || continue

    c=&quot;$(GetFileInfo -d &quot;$f&quot;)&quot;
    m=&quot;$(GetFileInfo -m &quot;$f&quot;)&quot;

    ec=&quot;$(date -j -f &quot;%m/%d/%Y %H:%M:%S&quot; &quot;$c&quot; +%s)&quot;
    em=&quot;$(date -j -f &quot;%m/%d/%Y %H:%M:%S&quot; &quot;$m&quot; +%s)&quot;

    if [ &quot;$ec&quot; -lt &quot;$em&quot; ]; then
        SetFile -m &quot;$c&quot; &quot;$f&quot;
    fi

    if [ &quot;$em&quot; -lt &quot;$ec&quot; ]; then
        SetFile -d &quot;$m&quot; &quot;$f&quot;
    fi

done


How the shell script works:

for f in &quot;$@&quot;; do -- For each file do something.
[ -f &quot;$f&quot; ] || continue -- If it's not a file, then go to the next item passed.
c=&quot;$(GetFileInfo -d &quot;$f&quot;)&quot; -- Gets the creation date of the file.
m=&quot;$(GetFileInfo -m &quot;$f&quot;)&quot; -- Gets the modification date of the file.
ec=&quot;$(date -j -f &quot;%m/%d/%Y %H:%M:%S&quot; &quot;$c&quot; +%s)&quot; -- Converts the creation date to the number seconds since Epoch.
em=&quot;$(date -j -f &quot;%m/%d/%Y %H:%M:%S&quot; &quot;$m&quot; +%s)&quot; -- Converts the modification date to the number seconds since Epoch.
if [ &quot;$ec&quot; -lt &quot;$em&quot; ]; then -- If the Epoch creation date seconds is less than the Epoch modification date seconds, then:

SetFile -m &quot;$c&quot; &quot;$f&quot; -- Sets the modification date of the file to the creation date of the file.


if [ &quot;$em&quot; -lt &quot;$ec&quot; ]; then -- If the Epoch modification date seconds is less than the Epoch creation date seconds, then:

SetFile -d &quot;$m&quot; &quot;$f&quot; -- Sets the creation date of the file to the modification date of the file.




Notes:
Epoch (00:00:00 UTC, January 1, 1970; see time(3).


Example Automator workflow:
Just add the parent folder containing the .wav files to the Get Specified Finder Items action and the rest of the actions.
Note that this is just an example, the main part is the Run Shell Script action, so however you want to pass the target files to it is your choice.