I believe nobody should expect anyone to do anything just by being present. It’s your life and you have your duties. So I guess it would help to set boundaries, e.g. by writing them in your profile. Like “I am a busy person and I reply to you within a week”. Or “Please only expect me to answer questions about X and Y, for the rest wait for the community”.
So I think it is more of a problem of the other people. Like if they would see you somewhere in real life and rush to you with something very important you have to do right now!