@teyson easy enough. Luckily your charging board is easily replaced and does not cost to much. Since iFixit does not yet have a guide for that, use the one [https://www.nadiemellamagallina.com/en/manuales/smartphones-1/samsung-4/samsung-galaxy-a21s-1238/placa-auxiliar-11037|from here] It was written in Spanish so use a browser that will translate it for you, if needed. Remember to check the flex cable from the charging board to the main board. Those can tear and/or get disconnected. Make sure that yours is in good working order and properly connected. Replacement 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 the same problem 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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