Blockchain

I'm planning to build a cryptocurrency wallet app, in the end, I'd like to also add NFT's to the app and be able to access their details (smart contract, token id, blockchain) but I haven't figured out the process on how to do this so far.

Would it be possible to do these using SDKs like Blockchain /Coinbase or should I start from scratch? If so, which kind of architecture should I use? I am hesitant to use ETH as the starting point as the transaction fees are too high for testing.