LED display weak and hard to read. runs constantly

Verify the humidity reading with another device. Perhaps the humidity sensor is dirty or bad.

Another possibility is the switching device that runs the compressor and fan is shorted. If it's a mechanical relay, the contacts may have welded together, or if it's a solid-state relay, it's got a punch-through or meltdown in a device junction. My guess is it's a mechanical relay since you mention it used to click on and off and now you don't hear that. The relay may be on the control board, or it may be mounted separately - I don't have a photo or diagram of the inside of your model available.

if its a newly mfg unit then yes the fans gonna run all the time , that's done to increase efficiency , if you hold down on arrows then you should be able to adjust the rooms humidity level, the default screen is the actual rooms humidity level , if you hold down mode button , this will cycle thru some timer modes that ind on the display

it should turn itself off when bucket is full , this even stops that fan from running most times

wow it seems you really have a lot of moisture , 1st i suggest you find and seal location of water entry second you might have to consider getting a second unit or a larger unit to work as your primary and save smaller unit for use as a back up
they are rated in Pints per hour the bigger the number the more water they pull out of air sounds as if your gonna need a 60 PPH unit or larger

Btw : 70%rh is considered the "normal" of the avg home
yours at 90 % rh is unhealthy for humans and will promote respatory mold growth and all its complications unit setting of 65% is telling me that unit is too small to handle amount of water you have

Probably some glitch with the sensors. I recommend taking it to a service center.

It sounds like the humidity extraction level is set to high. Lower it to 35% and check the air intake filter to see if it needs cleaning.

Read the instruction manual thoroughly and ensure you did everything exactly. If it still doesn't work it is faulty and should be returned.

I have the delonghi DEN500P and the unit runs but does not condense any moisture? The appropriate buttons have been set to bring the unit humidity setting well below humidity in room

it should shut off when the compressor is not running. only portable a/c can have fan running constantly

You have a bad fan motor. Put your hand against the grill to see if there any air movement. You need to buy a new fan motor assembly, it is attached by two long
bolts, easy to swap, except the wiring may not be easy. May have to cut the 3 wires and resolder. Get to the motor by removing the back panel and then the fan. Removing the fan may not be easy, they put some gunk on the spidle thread.

The cheapest price I have seen for the motor is $27-$28, shipping about $8 and tax
about $1.5.