The surveillance in question targeted Carter Page specifically. There were FISA warrant applications with errors and omissions. Two of four warrants were eventually declared invalid in 2020. Special Counsel John Durham is investigating the investigation. So far it looks like he's produced one acquittal, and an upcoming trial against a Russian national, Igor Danchenko.
You need actual evidence Biden was involved in the situation. All there is right now is Hunter possibly referencing his father. This is on the level of "Russia, if you're listening..." except in that case we know an actual outcome that appears to have coincided with the call for action while the venture Hunter proposed never occurred.