Hi,
Apparently this issue has been around for some Pixel’s for a while and the outlook isn’t good.
Here’s a link to some reddit chats that discuss the problem.
https://www.reddit.com/r/GooglePixel/comments/108qal4/pixel_5a_shut_off_and_wont_turn_back_on/
Not sure what your options are but there was some mention of Google extension on warranty but you’d need to check that out for yourself.
A repair shop may assist you with identifying if it will have any repair support from Google.
Hope this helps you to find a resolution or replacement.