IKEA Dirigera Hub Matter/Thread devices fail in Apple Home

I've been troubleshooting issues (for weeks) that involve IKEA Dirigera Hub along with various IKEA Matter over thread devices (mostly Grillplats plugs and Kajplats bulbs). Setup includes a number of Philips Hue bulbs and hub (working fine for years, show up in Apple Home), a Dirigera hub with 18 legacy Zigbee IKEA devices (again working great for years, showing up in Apple Home) and a handful of Grillplats plugs and Kajplats bulbs (work perfect with IKEA hub but will not stay connected with Apple Home app). Apple devices include a AppleTV 4k (older generation, not Thread) and a recent HomePod mini. Most of our control is through an iPhone 12 and 13 pro. Everything appears to be updated to most recent firmware. Also set up a separate ioT wifi network.

In summary, can't get IKEA Dirigera to share Matter/Thread devices with Apple Home. Here's a better summary:

DIRIGERA firmware 2.975.2

GRILLPLATS firmware 1.46

Apple Home sees 18 bridged Zigbee devices, but none of the IKEA Matter devices

No GRILLPLATS plugs or KAJPLATS bulbs are exported by the IKEA bridge to Apple Home

Direct Matter pairing in Apple Home succeeds initially but ends in "Updating…" → "No Response"

KAJPLATS bulbs also fail to pair properly in Apple Home

Anyone else having a similar issue?