How google finds out my accounts are associated?

Hey all! At first, sorry for my english.

I make webview doors to get commerce traffic for conversion by CPA model.

In every app i make some changes: garbage classes, strings are encrypted, in mainactivity i change code. Also i use ProGuard obfuscation.
But almost every app contains some files in assets wich are the same (but i change their filenames). Also manifest is the same (i mean everthing but appname).

I follow a rule: 1 google developer account for each app. So sometimes i buy google developer acc’s, and sometimes i’m registering them by myself using virtual cards. I always use different dedicated server to upload app, but i always use dedicated server where i registered google developer acc.

SO THE QUESTION IS: how google finds out accounts associasion and suspends my acc? Is it non-unique code? Is it same android studio used for app compilation? Is it something else?

First thing people think: same IP: wrong
Last thing people think: android studio on the same machine: bingo!

But where is the footprints of android studio? in apps sign for store? in METAINF? where? What do you suggest? to install android studio on each VPS? which way will be best?

Now i know. It is because of GP accounts have been bought with virtual credit cards.