I can’t update any of my apps and have signed in and out of my App Store more than 5 times now ... what should I do

Hi there, ινώfromαθήνα!
Thanks for reaching out to the Apple Support Communities! It sounds like you have an issue with updating your apps due to an error message when you try to update. I appreciate the screenshot and am happy to help out! Based on the message you are seeing, I recommend taking a look at this article to Change or remove your Apple ID payment information. This will allow you to verify that your billing information is correct.
I also recommend taking a look at this article If your payment method is declined, or you have a billing issue with a previous purchase in the iTunes Store in case you have an issue updating the payment information.
Cheers!