Unfortunately, we are reliant on Shopify to raise your store's API call limit.
Currently, Shopify are not able to raise the API call limit for stores on the public version of Syncio.
A special free upgrade for Shopify Plus accounts if you reach our to your Shopify MSM and ask for a "rate multiplier increase for public apps". Through this Shopify can increase your store's API call limit which increased the number of syncs your store can process per second.
We are also exploring a private app version of Syncio, "Syncio Plus" that can have an increased API call limit. Please inquire with the support team to find out about eligibility. Only available to Shopify Plus merchants.