Why don’t you spread out beyond expat and tourist land? If you are looking to eat Thai food in particular, Sukhumvit isn’t good by Thai standards.
Some contrarian ideas -
For a spectacular evening river view - The Deck at Arun Residence, Chao Phra River
Night Walking Food Tour - Chinatown at Yaowarat Road, easily reached now by MRT now.
Getting out and chilling out - Koh Kret, chilled out island on the river in North Bangkok. Not too far out, and you won’t feel like you’re in Bangkok.
Noveau bars/arts - Soi Nana, yeah not the one you are thinking of. It’s a street near Hua Lamphong Station of old shops that have been renovated into cool little bars and art galleries.
Bangkok is a mega-city, and options abound everywhere beyond a 3km strip between Nana and Thonglor BTS stations.