iPhone 12 Pro Max won't turn on

yesterday suddenly my iPhone turned of without any damage or reason and just never turn back on till yet, no apple logo nothing totally death i even try every methods such as force restart and so on, but no response even connecting with computer or mac

As my warranty expire i even not able to replace it with new one , i go to the shop and tgey suggest maybe battery probloem or some stripe problem maybe accure

any suggestions? what i have to do now

thanks in advace

[Re-Titled by Moderator]