As a Roblox developer and player, it’s currently not possible to recover deleted assets or avatar items. Many users of all ages have become a victim of account theft and have had their rare and/or expensive items deleted.
What I propose is a section in your inventory titled “Archived”, where items would go to upon deletion. This section should be private and visible only to the account that it belongs to. This would eliminate the need for the One-Time Restore feature granted by customer service for compromised accounts.
If Roblox is able to address this issue, it would improve my overall experience with Roblox because items that you want to recover will still be available, while items you wish to remove from your inventory will not clutter up space.