My phone suddenly died while charging

@ramarizkif87091 try a force restart first. Press the Power and Volume Up button for a minimum of eight seconds until the OPPO logo appears. This is also a safe method as it won’t erase any of your content. If that does not work try Recovery mode. Press the Power & Volume Down button for a minimum of eight seconds until you see the recovery mode menu and then click Reboot to reset system settings.

If that does not work it is time to check the charging port. Clean it of any debris with a few drops of isopropyl alcohol and a few puffs of compressed air. If you have a USB -C ammeter, connect that and see if your phone even draws any amps from a known- good charger. Next you will need to check the charging board as well as the ribbon cable that connects the charging board to teh main board. Disassemble it, check all the ribbon cables, check the battery connector and the battery. Measure the voltages from the battery connector or the USB port and see if that voltage even makes it to the motherboard. I would replace the charging board as well as the battery and then re-evaluate. Anything pat that point is a main board error. To work on that you will need to have the schematics, component layout as well as the proper tools to repair it.

Since iFixit does not yet have a guide for this, use something like this video to work on it. Once you have it opened up, take a couple of well focused pictures and post those with your Question. That way we can see what you see. Adding images to an existing question

While you work on your phone, take lots of pictures. Once you are done with it, take those pictures and create a guide for iFixit. That will help the next person that has a device with the same issues as you do. It's easy and fun to create these guides. https://ifixit.com/Guide/new The iFixit community will appreciate this.

Repair is War on Entropy!