Well, successfully installed PHP 5.6.40, 7.2.34, 8.03, so all 3 work, and here, MYSQL 5.6.46 works fine
after install, in Webmin you do have to change the control panel - all the directories for the setup / control to update the location of all the settings so that Webmin can also manage the install
it works perfect !
i would hope that Webmin offers a generic 5.6.46 install for many others out here who need a prior to MYSQL 5.7 install, i.e. 5.6.40