Apple ID is compromised, can't change password

Security and your Apple ID - https://support.apple.com/HT201303

"Without proof of your identity ... and other carefully selected criteria(1), Apple Support can't help you perform any actions on your account."

If you have lost control of your Apple ID and lack access to recover, and have insufficient documentation to recover access via Apple, there is nothing anyone else can do here.

You can gather up original purchase receipts showing serial numbers if those are available, and potentially regain control of devices locked to the now-unavailable Apple ID.

Change your Apple ID password - Apple Support

If you believe someone else gained access i would report this to apple.

If you think your Apple ID has been compromised - Apple Support