I was wondering, if it’s possible, to backup and create Amiibos with a simple NFC Tag App and not Apps like Amiiboss or the other Apps
I only have iOSTagMo is your best bet. I use it with my PowerTag, and it's great so far.

PowerTags are apparently sold out on the official website for me, but eBay might have them in stock. Another alternative would be to find an NFC reader/writer that can do both with NTAG256.TagMo is your best bet. I use it with my PowerTag, and it's great so far.
bought the powertag set from gamestop in-person. My local one still sells them.PowerTags are apparently sold out on the official website for me, but eBay might have them in stock. Another alternative would be to find an NFC reader/writer that can do both with NTAG256.
PowerTags are apparently sold out on the official website for me, but eBay might have them in stock. Another alternative would be to find an NFC reader/writer that can do both with NTAG256.

Yes, it's called Thenaya. You can backup and write Amiibos from (.BIN) files. In order to do so, you need to find the Amiibo encryption keys which I cannot provide.I don't know about all these other solutions, but isn't there a 3DS app for this?