We’ve done something very similar - using Google Sheets as a controlled input layer for non-technical users and then syncing it into a warehouse.
All the points about validation and permissions are spot on. The biggest improvement for us was adding a proper sync layer instead of scripts. We used Skyvia to pull data from Google Sheets into our DWH on a schedule, with some basic transformations and filtering in between.
It ended up being much simpler than maintaining custom scripts, and more flexible than some of the heavier ETL tools. Especially useful when you have multiple sheets or need to evolve the schema over time.