Is there a connection between rosacea and seborrheic dermatitis?

Not typical. These are two different dermatological conditions.
Yes. You can have features of both where the skin is red and present at the same time. It can affect the forehead and cheeks. Treatment would be for both components including possible two different creams and a low dose antibiotic.

Related Questions

Opinions on what's a quick way to treat rosacea/seborrheic dermatitis?

Nothing quick. Yu can help avoid exacerbations by avoiding caffeine, heat, intense exercise that leads to a lot of sweating. Avoiding vasodilators like wine and alcoholic beverages Medical treatments: several antibiotics Photo facials some chemical peels speak to a dermatologist all of there require several treatments.

I was wondering what's a quick way to treat rosacea/seborrheic dermatitis?

2 different disease. These are two different disease processes that require different approaches. Unfortunately there is no quick solution.