Pass Variable / Modal Detail debugging

Whats the best way to debug these „get“ ID variables, as I‘m having several troubles to get from a table list with Adverts my:

when one Modalform shows details, then the other doesnt and the opposite. But I‘ struggling with having mostly empty modal forms. So query isnt passed properly. Maybe the variable with $GET doesnt work good. But in general whats the best practice to debug modal/get variables? Maybe I better go with a separate page called updateAdvert.php and updateCustomer.php but that way I blow up my project :thinking::disappointed_relieved:

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