My Apple ID was vulnerated through a stolen iPhone

So recently someone stole my secondary iphone (iphone2) while i have my main iphone (iphone1) after i reported my stolen iphone and marked it as stolen by using find my iphone. After a while my main iphone iphone1 which had the same apple id account for iphone 2. My apple id email got changed on iphone1 to a random email now i cant get back my main email which i use for my apple id because i dont no the password for this random email i tried (forgot my password) but it sends an otp code to my old phone number that i no longer have since 2018. I really need an urgent solution please

[Re-Titled by Moderator]