Can I play Gutsy Pickaxe if I have no Benched Pokemon?
No, you cannot. Since it is mandatory to attach a Fighting Energy if you draw one, you have to have a Benched Pokemon in order to play the card.
Source: TPCi Rules Team (2022-06-09)

Relevant cards

Note: All applicable cards may not be listed below.
SWSH10_145
SWSH10_145