Ps vita PS button bink ones(orange) and then stays solid orange

Hi

My cousin child had a vita which was not been used in a 3-5 year period and was completely off.

If i connect it to wall charger(it’s own or any other one with sufficient out put) the PS button blinks once in orange and then stay solid orange and after some times it goes off(STH like 50-60min).

What troubleshooting i have done:

1- tried different charger with the same or higher (2A-5V) but no luck.

2- tried to hold down power button for 30 second to turn it off completely(did some search and find out other have been successful with this method) and then 5 second to turn on but nothing.

3-took it apart and disconnected battery and waited 10 second nothing

4- after step 3 i did let it to be disconnected about 1 full day but still nothing

any suggestions?

thnx

PS: I’ve seen this topic(Vita won't turn on. Solid orange charging light?) and he was sure the battery was good