Is Red Velvet really a good group to practice dancing?

I would have recommended you BIGBANG or Mamamoo at least the choreography won't take very long to learn

sure why not. their choreo isn't difficult. what you need to find though is slowed down Kpop choreos so you don't have to pause often. that is more important.

It's not very complex, so yes, good starter choreos.

Yes their choreos not complex. You can start with; Red Flavor and Russian Roulette. Both song is very fun choreos