Firebase : Saving Document ids in a separate document for reducing reads

I have an app with several pages and I am seeing my document reads surge a lot.

So I have this page where there is a list of values (which are documents in a collection) and user can add to that list by clicking a button on that page. Every time user loads this page firebase counts every document in that list as a read and my read count goes up by a lot.

To avoid this, I am thinking of creating a document which contains an array of map values with each map value having the id of my documents and an easy to reference name. So my repeating list can be based on this single document and I will have only 1 read irrespective of how many value/documents are in the repeating list.

The problem is I am unable to get patch to work to add to the array of values. Is patch the way to go about this? I read somewhere that you cannot patch with REST Api to add to array on firebase - if this is the case then what could be an alternative approach to reduce my reads?

Another option could be to use a client-side cache to temporarily store the list data and avoid having to perform the query every time the page is loaded. You could also program it to only update the database every 24 hours, or every 3, 4, 5 days, reducing the number of calls to the REST API.

That method is right here, you just need to search in the help magnifying glass.