I successfully upgraded my router box once I added the patch below.
The journey is described on bugs@[1].

diff --git a/sys/arch/amd64/conf/RAMDISK_CD b/sys/arch/amd64/conf/RAMDISK_CD
index 878eb5f3331..cf52f881fb7 100644
--- a/sys/arch/amd64/conf/RAMDISK_CD
+++ b/sys/arch/amd64/conf/RAMDISK_CD
@@ -58,6 +58,9 @@ com*		at acpi?
 glkgpio*	at acpi?
 pckbc*		at acpi?
 
+puc*	at pci?			# PCI "universal" communication device
+com*	at puc?
+
 efi0		at bios0
 mpbios0		at bios0
 
I'm not sure if this is the right thing to add, much less at this point.

[1] https://marc.info/?l=openbsd-bugs&m=177653050704016&w=2

Thanks
Greg