I accept that IGMP is big for your use-case and that your are understandably un-impressed, but I would guess the set of people that consider IGMP a key feature of turris OS is not all that large…
BTW, just released OpenWrt 22.03.03 just temporarily dropped mvebu* devices like the turris Omnia, so be careful where you update to next.
*) OpenWrt snapshots have this fixed the same way as turris OS did, by switching to kernel 5.15.