1. You can not recover deleted power apps if they are not part of a solution but you can restore deleted flow whether they are part of a solution or not. There are the two ways you can restore deleted flows.
- Use the Power Automate Management connector to restore the deleted flows.
- Use Power Shell to restore the deleted flows.
2. You can restore it within 21 days of deletion.
You can refer to this Restore deleted flows for complete steps.