Hi there. First time poster! I'm very new to houseplants (recovering black thumb). I bought a Kentia palm on July 1st. When it was delivered, they told me to water it "very generously" to compensate for the stress. Then, they said to water it every week or so afterwards with enough water "so that it starts draining out the bottom into the pan."

So, since then, I have only watered it once, at which point I poured a several small buckets worth of water into the pot and never saw any drainage into the pan. I got worried that it wasn't draining well and I was going to drown the pot, so I let it be.
Since then, several leaves have turned entirely brown, and several stems are no longer strong enough to hold up their fronds and have bent, so that the frond grazes the floor.

I ordered a soil moisture stick from Amazon, and every time I put it as far into the soil as it'll go, it reads 9.9, which is the highest (most moist) reading. So I keep not watering it, afraid to drown the plant.

Today I called a local plant expert to try and help me diagnose the problem, but he's not super familiar with this type of palm. He told me to dig up the dirt near the sides and see if it's indeed not draining properly; based on all of my descriptions, he expected that I'd find mud. Anyway, I used a small trowel to dig pretty much to the bottom of the pot, and while the soil felt moist, it was by no means wet or soaking or soggy or compacted.

I guess my best guess now is to insert something between the pot and the pan, in order to help get oxygen flow to the roots. But maybe the issue is that I've been underwatering, not overwatering? Or maybe this is all just from the stress of the move and different conditions?
Thanks in advance for your help.