Which wound you get.. sigma 30mm f1.4 vs sigma 18-50mm f2.8

I found myself using the kit lens zoomed in to around 30mm for most of my shots although obviously the variability is nice.

However, I mostly take candid pictures of my family inside, take picture of my kid running around, etc. Lighting is variable and never certain.

For that reason, I really think the f1.4 wins out for me. I’ve used the 16mm f1.4 and found that in certain cases even the 2.8 isn’t enough light to take a picture without cranking up the iso past 3000.

I’m purely an amateur take pics of my family guy. Taking pictures is never the pure purpose of anything I do, just something I like doing when the right moment comes up. So I’m heavily leaning to the 30 bc it’s cheaper and more versatile in terms of lighting. Thoughts?