just saw a video review of the OB-X8(sonic state, Nick Batt) and it has a very nice feature in the arp section.
you can hold an arp and then “lock” it, so it plays and you can play on top of it without changing/triggering the arp again.
that would be a nice feature also on the UDOS6.
maybe with a long press on HOLD (until it blinks)… if that is possible.