Best firmware for Ikea devices

[GreenRover]

My installation worked for 1Year
But since i add 2 more device i run into problems like:

All changes results into:
Publish 'set' 'brightness' to 'wohnz_decke_fenster' failed: 'Error: Command 0x90fd9ffffe5976a5/1 genLevelCtrl.moveToLevelWithOnOff({"level":127.5,"transtime":0}, {"timeout":10000,"disableResponse":false,"disableRecovery":false,"disableDefaultResponse":false,"direction":0,"srcEndpoint":null,"reservedBits":0,"manufacturerCode":null,"transactionSequenceNumber":null}) failed (Timeout - 57120 - 1 - 8 - 8 - 11 after 10000ms)'
But the change worked. This makes every thin incredible slow.

I loose constantly device that have to be coupled again.

We talk about 9 different Ikea devices.
Connected to an: CC2531
I tried different version of zigbee2mqtt

What firmware for the CC2531 do you advice?
Or if a different adapter would help? Where can it be ordert? (All published links are out of stock)

Best regards Heiko

[GreenRover]

Another problem seams to be that most devices choose one of the 3 light bulps that are power less from time to time as router.
Ca i setup the router that have to be used?