Hi @Gregor Anton Grinč ,
regarding your question "am I right when I say that after the disassociation of public standard IP or moving it to another subscription or resource group the IP address will always stay the same? (Meaning 100% of the time)."
I moved a Public IP a few times between 2 subscriptions forth and back for testing. The result was always the same: The Public IP was always the same before and after the move finished.
I won't give a 100% guarantee ;-) but I am very sure the Public IP will be the same.
(If the reply was helpful please don't forget to upvote and/or accept as answer, thank you)
Regards
Andreas Baumgarten