I would like to grab some food there and then search for a place with a good view pf the firework.

yeah yaowarat will be absolutely packed with food stalls that night, no worries there. for fireworks, the rooftop bar at river city is a solid spot if you can get in, but they usually do a ticketed event. another option is the hua lampong side streets near the river, less crowded than the main riverfront but you still catch the show between buildings

if you want a less chaotic food option, the sois off yaowarat like soi 16 have smaller stalls that are still great but less of a madhouse. for fireworks, the river city mall area is actually decent if you get there early enough, or try the balcony at the sheraton on charoen krung road. just be prepared to pay a premium for a drink minimum anywhere with a view

if you want food AND a fireworks view without fighting the river mob, try the pier at rachawongse. it's a short walk from yaowarat, the ferry stops running after 6pm so it gets quiet, and you can see the main show from icon siam across the water. grab grilled squid from the stalls near the yaowarat intersection first, then walk over around 11pm

yaowarat will be in full chaos mode food-wise, that's a given. for the fireworks, try walking over to the memorial bridge (saphan phut) area, theres a small pier park on the thonburi side that gives a solid view without the river city crowds. just get there early, like 9pm early, and bring cash for the street vendors that set up along the bridge itself

if you want food without the yaowarat crush, walk over to trok itsara nuphap alley just off the main road. small stalls there that locals hit up, still open nye but way less tourist gridlock. for fireworks, the temple pier at wat mangkon kamalawat gives you a decent sideways view over the river without fighting for rooftop space