More fertilizer will help. Bananas are very heavy feeders. I typically fertilize mine twice a month, but I give them the recommended "once a month" dose of fertilizer. It's probably possible to over-fertilize banana plants, but I've never managed to do that.

You also might need larger containers. I have two "superdwarf Novak" banana plants. Mine are in 20" diameter planter pots, which is over 20 gallons (about 3 cubic feet) of potting mix/soil per plant.

Some "drop off" of the bottom leaves is normal. But mine typically keep almost a dozen green leaves before the bottom ones start yellowing/browning. I trim them off when they start getting brown, although you can let them brown until they break/fall off. Once you have more green leaves, you should have a balance between new leaves emerging at the top and old leaves dying off at the bottom. In the summer, mine grow two to three new leaves every month.

They look very water starved! The plants need much larger larger pots! 10 gallon minimum to support their rampant water transpiration rate. And they will grow fast too.

This Basjoo pictured below went from little shoot in 4" pot to 4.5' plant with multiple off shoots last summer! Hardy here so ground planted last fall to make a little grove.

Leaves trimmed, base mulched, and tarp tent covered now for winter. Many folks here give them no protection and do well, but ground planted it late in season.

Yes much larger pots indeed or even better in the ground!