The charging icon shows but immediately disappears

@mulankanye heck your charging board. Make sure that there are no burned or damaged components on that. I would replace charging connector flex as well as the battery and then re-evaluate. This seems to be related to the charging circuit, possibly an issue with the power management IC.

Since iFixit does not yet have a specific guide for that, use the ones from here They are written in Spanish so use a browser that does the translating for you (if needed)

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!