Ok, sucheendran, I’ll try… you can’t expand/upgrade the internal storage ( and RAM) as the SSD and other components are soldered directly to the logic board and are built to order… so that leaves external storage … so an external SSD with usb-c/thunderbolt 3 connector/plug or usb 2.0 would work fine.. you can buy them up to 4 TB in size, you have 1/4 of a TB( 256 GB, 1000 GB= 1TB) so 2TB would give you 8 times your current storage capacity. 1TB would give you about 4x your current capacity. The only disadvantage might be the cost…this link is to a vendor so you can see what is roughly available from that vendor and the approximate cost ( in USD).https://eshop.macsales.com/shop/owc-envoy-pro-sx There are lots of other vendors out there, and you’d probably be able to find someone closer to you, eg who is in the same country that you live in, who uses your local currency, and who has what you’re looking for/need. That should help with your storage problem greatly. Why on earth do you need to format and so often , i don’t know. Your Mac and the Mac OS will need enough free system storage space to successfully work and temporarily store stuff, although you can sorta reduce that a bit ( managing app storage data in Catalina/Monterey/Big Sur, look it up) .. but not a lot… so, get an external SSD..
john