I don't know why it's so difficult to maintain my Pindo Palm trees. From all the research I've done, I still can't find out if my plants are dying from being over or underwatered. It's been pretty muggy and rainy for a few months here in Austin TX but looks like it will be sunny again for awhile. I didn't water them while it was raining but I have been a few times a week lately since the rain stopped. The soil is moist but not soaked, it seems to be fully draining down to the bottom where the roots are. I have 2 little trees and the soil moisture on my meter shows the same for both.

The first 2 pics is my really bad tree, all the new fronds are dead except 1 and the older green fronds are drooping.

The last pic shows the new fronds are staying healthy, the older ones are dying or dead already.

I am thinking to little water. The palms have become to large for the pot. Lift the palms out of the pot and you will more than likely see just a mass of roots. The mass of roots causes the water to run right out and your palms do not get a chance to absorb the moisture to the entire root mass,

These trees are barely a year old too. Maybe like 9 months.
I've been using a fast draining soil too. Idk if you know anything about it.

The bulbus look to the trunk indicates the palm is becoming stunted in the pots. Potting soil you are using is fine for the Pindo. Did you acquire these palms in these pots 9 months ago or did you repot? The Pindo will be much happier planted in the ground or at least for now moved to a larger size pot. Trim off the totally brown fronds and treat the center growing point with 50% hydrogen peroxide 50% water mixture to ward off crown rot.

The Pindo is a tough palm, but I will warn you the palm in your first/second photo maybe a little to late to save, but no harm is done trying.

I was thinking over watered from rain, but if rootbound, they could be under watered, as both ways perty much has same effects.

I hope pots have drain holes.
Pull them out. Like, now.
See if roots are healthy.
If there rootbound. Put them, less pot, into a bucket full of water for a good half hour, them rub rootball to loosen up some outside roots so they can grow out of rootball.
Then treat with peroxide water and up-pot them as @ScotTi recommend.
For new soil, I'd use equal parts of perlite to soil you have. Barley moistened, then wait a week to water.

If roots are rotten, remove all rotten roots. Do peroxide thing. Put some cinnamon on cut root ends. Then repot, with fresh soil as I directed above.

Best, to you, and them.
Philip 😎😎😎