What lens to choose? Maybe both?

Hello everyone,

I have a Sony a6500 with a 18-105 f4 lens.
I would like to shoot videos inside buildings more, maybe with low light as well and as I experienced, with this lens doesn`t really work well…
I don`t have a really big budget for upgrade, but I would like to have a much faster lens.
What I was thinking of:
Sigma 30mm f1.4
Sigma 19mm f2.8

Do you guys think, it`s enough to buy one of them, or would my kit be more “complete” if I buy both?
Some of the rooms are quiet small, so I need wide lens, but many people recommending the 30mm, which would equal 50mm on the a6500.
So I can`t really decide…
If you have any other suggestions, would be much appreciated as well.

Many thanks,

David