Sales Channel App Scenario

Hi Experts,

I am facing a project that still have a doubt if is candidate to a SALES CHANEL app.

A Similar scenario has been discussed in this thread 2 years ago :

https://community.shopify.com/c/shopify-apis-and-sdks/multivendor-marketplace-implementation-on-shopify/m-p/547098#M36144

But due the long time I would like to confirm some points …

A Marketplace Operator would like to have an app to turn EASY merchants publish product into MARKETPLACE SITE …

But in their Business Model … CONSUMERS will be able to have a CART with products coming from SEVERAL DIFERENT MERCHANTS … and the Marketplace want to handle the payment part as

ONE MARKETPLACE ORDER … can be TURNED into several ORDERS for different MERCHANTS …

So It seems the app should user ORDER API … but NOT CHECKOUT API …

And based on my understanding … this will turn the app as a NON SALES CHANNEL APP , correct ?

Best Regards