I believe the bolded part in the previous quote above is still largely relevant today/tomorrow, with some adjustments of course (eg perhaps Guam instead of Singapore ... but also noting the likes of modern Singapore and its neighbors have their own modern and capable armed forces. Of course the USA plays a dominant role in the region whereas the UK doesn't, and Australia's capabilities across the spectrum or domains is first class), but would modify it to become roughly in this order, give or take:
(a) local defence.
(b) forward defence, involving our closest SW Pacific neighbors eg New Caledonia, Fiji, etc (and likely to be in conjunction with US, France, Australia anyway).
(c) assisting with the defence of Australia.
(d) the defence of shipping routes (primarily Tasman Sea, South Pacific and Southern Ocean but where practical also stretching from SE Asia to South America, as we did in WW2 with the RNZN Light Cruisers).
(e) SE Asia, Indo-Pacific ... Middle East, Europe etc.
(f) but also as well as kinetic efforts there is also cyber and space warfare to contend with (even if there were no direct military threat).
Of course we cannot do this all, in fact we can't as we are not a major player (apart from perhaps sending some niche elements to contribute to collective allied defence efforts if and where practical), but what will be expected to do at the very least is is to defend our own wider "neighborhood" so as to ensure the major players (USA, Australia etc) do not need to devote their critical resources away from their major areas of operations.
Of course also this is a multi domain effort but bringing it back to the ACF in a NZ/Pacific context (not expeditionary) ... again as per the bolded/quoted part for local defence (and ideally forward defence as in protecting the SW Pacific) an ACF (in conjunction with P-8A and long range maritime UAV assets & Navy) would likely be desirable to assist with the defence against the likes of submarines, raiders, merchant vessels (with concealed armaments, mine laying capability, potentially missile launch capability, perhaps in containers for example or aerial ISR assets etc), dozens if not hundreds of gray zone vessels that are likely to still be operating in the wider South Pacific region perhaps some of which also conducting signal/intelligence gathering and/or harassing merchant vessels or conducting sabotage on island or undersea infrastructure (data cables etc) and potentially the odd warship or so that could be transiting the region (even Iran sent a warship through the region a few months ago).
I don't think we necessarily need the latest 5th generation fighter (at this point in time) as we are not likely to face a peer threat, but something existing (4/4.5 gen & new or second hand initially) tasked to work with the P-8's and the proposed long range maritime UAV's would both protect and support these platforms (as well as needing a decent logistics tail and the critical trained personnel - but RNZAF tends to fair well with recruitment and retention anyway).
