posted this on SharePoint stackexchange but this seems more appropriate
Is there a recommended way to link workbooks that are kept in Sharepoint/Teams?
I have a setup where many different projects have a spreadsheet for tracking various items and then one central spreadsheet pulls certain data from each of those individual files and summarizes certain info.
Typically you can just have both files open and in the "summary" file start a formula and then go to the other spreadsheet and click in the cell you want to reference and all is well.
It seems to handle the fact that it is a Sharepoint file (synced locally) but the actual link that it uses seems to get broken as soon as you close the file(s). The next time you open the summary you have to recreate the link.