@jonjo70099 you are not specifying if this is the 4G or the 5G version.
This sounds like an issue with the charging board or the charge controller. I would suggest to change the charging board (possible issues with the charging port, which is soldered to the charging board). If a replacement does not resolve it, it is possibly a board issue (charge controller). For that, we would need to know the exact model for your phone. Hopefully schematics will be available for your model.
Since iFixit does not yet have a specific guide for this task, use the guide [https://www.nadiemellamagallina.com/en/manuales/smartphones-1/samsung-4/samsung-galaxy-a13-sm-a137-1378/placa-auxiliar-12494|from here] It was written in Spanish so use a browser that does the translation for you (if needed) Charging boards are readily available at many online stores.
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.
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