iPhone battery health drop out

You can't see the actual numbers, because Apple rounds them down.

The 94% that you saw may very well have been 94.0% and the 93% that you saw may very well be 93.9%.

But, to be very conservative, Apple always rounds down the actual number. So, while it may appear to you that your phone dropped from 94% to 93% in 3 weeks, it may have only dropped .1%.

In general, you should expect that Battery Health will decline an average of about 1% a month. But....that's an average. Some months it might not drop at all, then drop 2% the next month.

You will drive yourself crazy if you are checking the battery all the time. The only thing that really matters is that you need to replace the battery when it is down to 80%.

No worries its normal ageing of battery ! Better use it and not check every day battery health , it creates panic atacks :)