Poor 4g lte coverage at my home Peoria, IL 61615

I have been with T-Mobile since the mid of 2017. I have started using a signal booster from mid of 2018.
My device is Iphone 8 plus which supports 4G LTE with ease.

Lately, the signal strength is poor. I see at most 2 bars on my phone if i'm lucky and usually it's just 1 bar.