No. The whole point of the Defiant is that it's just a warship, one, albiet, that was multirole. One that was supposed to operate in teams. But because it was one of the first to be laid down after the Borg, it was shelved quickly and never mass produced; only two/four ( I think we see four in one battle but they weren't working in tandem, which defeats their purpose in part!).
However, it can do *recon* well, and has good scanners for that purpose; so if there ever was a Federation Expeditionary Corps, it wouldn't be totally blind. Two hundred years of inertia, I guess.
Heck design wise. the Defiant is just a saucer with engineering shoved into it, the warp nacelles glued on the side and the deflector array shoved in front.
No.
That said, I'm sure there's an episode where the "stripped down warship" sprouts a science lab. Trek ships are super convenient like that
It's on Deck 2, I believe.
"In its limited role as a reconnaissance starship, the
Defiant-class was equipped with two dedicated science and medical labs for field testing and investigations" - Memory Alpha.
Should had just stripped them out for a Science closet and filled the space with more quarters.