I’ve definitely not experienced this and I use a CC2531-based network in a very large home with about 40 zigbee devices. My setup was originally deployed for Zigbee a few years ago and has been pretty reliable. A quick Googlin’ indicates that the MAC access error can be caused by WiFi interference though. Have you tried changing the zigbee channel?
EDIT: Meant to include the link to the zigbee docs about the Mac access error you’re seeing. https://www.zigbee2mqtt.io/guide/faq/#common-error-codes
Damn good bot!