You are correct, if you are using Collections that you will have incremental 'collects' based on the app setting. This is 500 by default, but can be incremented to 2000.
This can be accomplished (albeit jerry-rigged, but you indicated it's okay), by importing the Excel file into the PowerApp as static data. Simply determine a mechanism to 'page' the records in appropriate increments. Then you can create a Collection that indicates the groups, and do a ForAll function against that Collection. For example:
- Collection indicates you have 4 'groups' of 500 records
- Each collection record has the start and end row for the group
- A ForAll function loops for the 4 collection records
- It filters the dataset for the 'group'
- It patches that dataset to SharePoint
How many rows in Excel total?
Are you able to add a column to help page/group the rows?
Also, if you import the Excel file. You may be able to simply ForAll against that table and Patch. It may not be subject to delegation limits, but I am not sure.