The practices that might help the Product Owner minimize waste in developing and sustaining the Product Backlog are:
Remove items from the Product Backlog that have not been addressed in a long time. This helps keep the Product Backlog relevant, concise, and focused on delivering value. Items that have not been addressed in a long time may indicate that they are not important, feasible, or desirable anymore. They may also clutter or confuse the Product Backlog and make it harder to order and prioritize.
Only fully describe Product Backlog items when it seems likely they will be implemented. This helps avoid spending too much time or effort on items that may change or be discarded later. Items that are likely to be implemented soon should have more detail and precision than items that are further away or uncertain. The level of detail and precision required for each item depends on its order, size, and complexity.
Other options, such as avoiding distracting the Scrum Team by maintaining newly gathered Product Backlog items in a separate Product Backlog until they are fully understood or handing off ownership of the Product Backlog to someone else, are not practices that might help minimize waste in developing and sustaining the Product Backlog. They may actually create more waste by reducing transparency, collaboration, alignment, or ownership.
Reference:
[Scrum Guide], page 11, section "Product Backlog"
[Scrum Guide], page 6, section "Product Owner"
[Scrum Guide], page 12, section "Product Backlog Refinement"