It’s best to grind back to clean glass. That probably, but doesn’t always mean removing the flange. Then, you would add a fillet of thickened resin. I used cabosil, wood flour and chopped fibers to make a putty for fillets. I wouldn’t mess with roving. It’s hard to wet out, and there are stronger options. Two layers of Biax 1708 will be stronger than a layer of 24 oz roving, and easier to work with.
While you’ve got the section of deck removed, try to check the stringers as far back as you can see. It’s doubtful that the forward hull deformed away from the stringer, so I’d be concerned that the stringers have separated further aft too. Mine were separated aft, but well bonded forward. If you post photos, we can probably advise you better.