1. For now, If you don't have an override for your includes/languages/english.php, copy it to includes/languages/YOUR_TEMPLATE/english.php.
2. Then, you can change the define for ENTRY_TELEPHONE_NUMBER_TEXT to a null ( '*' becomes '' )
3. Next, in YOUR_ADMIN >> Configuration >> Minimum Values, set the Phone Number to a blank. It defaults with a 3. Just edit the setting and and hit delete should leave it blank.
Now your site will still have the phone number but, it is not required AND it will not complain about getting no input.
To Truly get rid of the listing on the pages, you'll have to figure out which of the over 160 files need to be changed to keep the phone number from showing up.
A dev could help with the template but PHP version is the responsibility of the host.
IMHO, a host that cannot provide 8.0 is someone you need to leave. A developer cannot change your PHP unless that version is available on the server. It is the responsibility of the host to keep PHP current on their server and available for use by their customers. 8.0 was released in November of 2020
I would give them a pass if it were 8.1 since it's new this year but, nearly two years behind?
