The best method if it keep booting with chime in sound and with or without apple logo, it keep on repeating and sometimes it sits there without loading. Then best method is to open MacBook Pro case and unplug the battery pack flex ribbon from the board. Then plug the charger and turn it on. Walaaa it works! And walaaa need buy new macbook pro battery. And you will notice your battery pack is a bit fat/bulky.
This is for MacBook Pro with flash memory/RAM solder on the board. 2015-2020