Shopify Marketplace Connect

I just spent an hour and a half setting up the first two products for all 5 Amazon marketplaces we have properly connected. After an hour and a half of work, I found that my work is not saving. Title, pricing, product category, tags.... this is desperate. The app is paid, so one would expect these basic functions to work reliably.
The app works as poorly as the previous app from Codisto, which I tried and uninstalled after 14 days. It's the one that only allows connection to one marketplace.

Standard so-so, Shopify-built app that reminds me of Shopify Flow. It does some things but not the things you want. It does not integrate with useful new features that Shopify has introduced - like Metafields. You spend many, many hours figuring out that it does not do these things.

Do you use a metafield to hold your UPC data? You're out of luck.
Need to refresh a SKU that you've replaced with UPC data so that you can sell it on eBay? You're out of luck.
Need to reset a listing that has errored out? You're out of luck.

If you have a customized Shopify store you're not going to enjoy this.

This extension doesn’t work inside Shopify app or admin from browser, for iPads or iPhones.

I've used this on and off for years. Has been very buggy in the past and 'gotten us in trouble' with amazon because randomly stopped syncing. I see that they now are charging 1% of revenue of synced listings, on top of their app charges, which I find unbelievably greedy. This must be some kind of monopolistic advantage. Anyway, you can't just push your listings to Amazon and be done - AZ is super complex and the listings must be highly customized.
After 5-8 years we are going to find another app due to this greedy policy change.
I suspect they changed their name from Codisto in order to avoid their reputation of poor service in the past. For some reason this is Shopify's go to recommendation and I have no idea why.

The interface of Codisto is integrated inside Shopify. While this might have advantages we found that it was difficult to work and navigate through the app.

Then, the app modifies the theme when installed. Even after uninstalling it some traces of software remain on the code so make sure to manually remove them.