Anyway to get the total supply of tokens in the contract?

I am reading some contracts deployed by Manifold studio, but I noticed that there is not a function of totalSupply which sometimes is standard in ERC-721, is there another way to get the total supply of tokens? right now I am going one by one until it returns an error using ownerOf , but I am sure there must be a cleaner way to get this.

gm! thanks for reaching out - Would love to hear a little more about what you’re trying to do here. Are you looking to get a list of your token holder?s

gm! Thanks for the reply,
I am building a website for a Web3 Artist, he has multiple collections out there, so I am getting data from all his collections including the total quantity of tokens per collection.
I am using web3.js to read the contracts and get the data, currently, it works but I am making so many calls to get the total quantity of tokens per collection that is probably not scalable