if there is any way to receive other cryto into cardano-wallet in the form of ADA, then please suggest how to do that for a Point of Sales (POS) system
I believe u will need a bridge like milkomeda
Seems like you are looking for auto coin conversion. Those are usually provided by payment gateway companies. I know that :
supports Cardano since there are some Twitch streamers that use it as well as integration with Shopify.
However, they are just a middle man and you will have to pay % of total charges plus network fees as a cost for EVERY transaction. It is much better to use service such as this to covert to fiat, then once a month just buy as much ADA as you want with that money. This will reduce your fees by more then half.
For PoS I would still set up Shopify terminal for customer to use, since that will be recognizable brand for many people. Maybe check out :
…before you look into crypto payment gateways.