An admin panel is used for hours a day by the same few people. That makes it the opposite of a landing page: nothing needs to impress, everything needs to be predictable.
The table is the product
Most business systems are one table with a form attached. Sorting, a stable row height and a visible count do more for the daily user than any dashboard.
Filters that survive a reload
Keep every filter in the query string. It costs nothing, it makes a view shareable, and it means the back button behaves.
Forms: fewer fields, clearer errors
Group fields by the decision the person is making, not by the database table. Validate on blur, show the error next to the field, and never clear what they typed.
What I would do differently
Write the permission model before the first screen.