Can I search the tasks(which can be find in the tasks panel) by telescope?

[LintaoAmons]

The item's name is the command or command's name
The preview is the tasks output
and after I the selection, a popup window will show like I use <c-f> in the tasks panel

[stevearc]

You can do :OverseerTaskAction to open up a vim.ui.select dialog to select a task, afterwards you will be presented another dialog to choose an action (in your example you would choose "open float")