Re: Dry brown leaves
From the pictures, this could be over watering. Picture of the 2nd plant appear to show a self watering pot. These keep water in the bottom of the pot. The soil at the top can be dry while the pot bottom is soggy. Bananas need 'fresh' water, not stale water. Use pots with drain holes that allow the water to drain out into a saucer and raise the pot if necessary to keep the drain holes out/above the the water.
Using your finger to check soil moisture is only good for the top of the pot. Get a long stem moisture meter to check the soil moisture in multiple places and levels of the pot. Wet at the corm and dry at the outer edges of the pot would indicate a bigger pot is needed and/or possible root rot developing.
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