There are two types of board filters to be aware of here:
Temporary (exploratory) filters — When you apply a date range or filter using the "Add Filter" dropdown on a board, these changes are temporary and do not alter the saved board for other users. They let you explore data without affecting the board's saved state. [Board Filters]
Pinned (permanent) filters — If you use the Pinned Filters feature (accessed via the overflow menu on a filter → "Edit"), changes are saved to the board. Since sharing and permissions are set at the board level, saving a pinned filter would update the board for all users who have access to it. You must click "Save" for these changes to persist. [Board Filters]
In summary:
Temporary filter adjustments via the dropdown = personal/exploratory, won't affect other users' views.
Saved/pinned filter changes = affect the board for all users with access (requires Editor permissions to save).
If you want a personalized filtered view without impacting others, the recommended approach is to duplicate the board and apply your filters to your own copy. [Board Sharing]