Hi Ray,
The Uppercase feature is located on Input field General option section.
There is a bulk option on the plugin where you can set default inputs that will be displayed on all products. It’s located on plugin’s settings > All products.
If you didn’t use it we can try to change it programmatically using the alg_wc_pif_field_html filter. I can help you with that, just let me know.
Regarding Safari, unfortunately it doesn’t support the pattern attribute so well, but theoretically, since version 11 it should be working.