What is the screen that you see, Samsung Logo, and then what happens, blue or black screen?
Battery was fully charged?
If you plug in the charger, do you see any charging information?
More information about what is going would be useful, like what were you doing before this happened?
Sounds like you are saying that it's stuck in a Bootloop.
Hopefully you have a recent backup, because you will likely want to have one after my next suggestion.
When the device looks like it has powered off, Press & HOLD the Power & Volume UP buttons, and see if you can get it to Boot into Recovery. If you can, you may see a bunch of red text, some of which may say that you need to wipe data
If you see the option to Wipe Data there, Select it. If you boot to the normal Recovery Menu, you could just wipe Cache, but I really don't think that will help.
So from the Recovery Menu (which hopefully you get), use the Volume button & scroll down to Wipe Data Factory Reset & Select it with the Power button.
If you're not sure how much battery is left, I'd definitely have your phone plugged into the charger during this!
Yes it's helpful.
Were you trying to Flash some Firmware?
You might have to take it to a Samsung Service center to get it resolved though.
Hi, We recommend you to visit the nearest Samsung Authorized Service centre to get your phone examined by the service technician to determine the root cause of the issue and get it fixed.
Please follow the given link to know the nearest Samsung Service centre. https://www.samsung.com/ca/support/service-center/
$400 to Flash the stock Samsung Firmware???????
Do you have a computer?
Did you have your photos backed up with Samsung Cloud / Google drive / or on any external sd card?
If you do have a computer & you can get the device into Download Mode, it's usually about a 15 minute job to Flash the Firmware.