How to calculate a product price hourly and days price?

Hi, you have put a lot of code and most of it has nothing to do with the question. But it's ok.

I would convert any unit of time (hour and day) to timestamp and use the smallest unit (hour) to calculate the price.

For example:

https://schoolsofweb.com/how-to-calculat...es-in-php/

PHP Code:

$date1 = "2021-05-27 01:00:00";

$date2 = "2021-05-28 02:00:00";

$timestamp1 = strtotime($date1);

$timestamp2 = strtotime($date2);

$hour_diff = abs($timestamp2 - $timestamp1)/(60*60);

$price_hour = 2; 

$final_price = hour_diff*price_hour;