Don’t try to play all the parts at once
One of the best things about the piano is that it can play everything from the melody, rhythms, and bass line, to harmony but just because you can, doesn’t mean you should!
When the piano is a solo instrument, there is no harm in showing off all the things you can do with it but when you are in a band, keep in mind that you are one of the band members.
If you are playing everything at once, you will overpower the other instruments. In an inexperienced band where the instrumentalists don’t stick to their roles, it can result in a mess of sounds that don’t blend well together.
What a good band should do is allocate the parts to the different instruments, so that there will be no clashes or competition between the instrument sound. Rather, the band should work together to complement each other and achieve a unifying sound.