SHINee and EXO probably fit what you’re looking for the most. Their discographies are very R&B-oriented and have strong focuses on vocal harmonies (you could say this about basically any group under SM Entertainment however). The former are more or less the boy group equivalent to Red Velvet as they have explored a lot of different sounds and genres, while the latter are more pure R&B.
Other boy groups I’d also recommend which have what you’re looking for are:
- NU’EST (have really good R&B vocals and dance songs)
- GOT7 (their singles are hit and miss (speaking as a fan) but their album tracks are very good and their more R&B songs are found there)
- ONF (think SHINee in terms of diverse range of sounds and concepts, but more pure-pop-oriented. But they also have strong vocals and harmonies)
- SEVENTEEN (this group has different sub-units dedicated to vocals, dance and rap, I think you’d like their vocal unit songs a lot)
-OnlyOneOf (their sound is very alternative-R&B)
Oh Thank you! This is exactly what I needed. I’ve tried with BTS but there are not really my cup of tea. And I will definitely check your suggestions out, Red Velvet is my favourite girl group within the K-pop universe right now!!