I wrote it several times, the UK is spending way too much money on naval force projection assets and on the navy in general. They have 2 carriers despite having just 17 surface combatants. 11 of these are frigates and 6 are destroyers. They have ~25 fixed-wing aircraft for that 2 carriers. So they can't escort a single carrier without using most (all?) of their deployable destroyers and they can't fully populate a single carrier with aircraft.
Anti-shipping capability of the UK is ironically anemic. The F-35 has no internally storable anti-ship weapon and it can't carry the Harpoon as of 2023. Most of the RN ships are limited to 8 Harpoons and most of the time they don't carry even that. Thus I am not sure if they even train for ASuW regularly. RAF aircraft have no dedicated anti-ship munitions as of 2023. So the UK's high-end anti-shipping capability is limited to torpedos launched by 7 submarines. The Astutes are very capable but submarines suck at active hunting.
I agree in the strongest possible terms. This is a 2nd or a 3rd tier force that simply cannot operate independently in a peer-level conflict. Forget sustainment, the only way the Royal Navy would be useful in a Pacific War, is if they simply fully integrated all of their ships/personnel under a US chain of command.
British Army and RAF have a lot of similar capability gaps. I recently wrote about the current lack of AWACSes. Temporary but a military with such a budget shouldn't have left with no AWACSes after a few old ones got retired. So, like you, I see a military that sacrificed everything except underwater capabilities to support Americans in GWOT-like campaigns.
Side note: After the Russian military got exposed recently, the need for smart military spending in Europe actually disappeared. I would go as far as saying all of Europe is overspending and better off just decreasing budgets. I used to advocate for more army spending and cuts to naval budgets, but it turned out it doesn't matter.
British Armed Forces in totality, need to have a serious conversation about what their priorities are, and what is truly a security concern for the realm. UK can meaningfully contribute to helping USA fight in the Pacific, but attempting to create their own CSG is just not it. But I get it. This is a country that's confused about their own destiny and their own aspirations, which is reflected in the nonsensical politics of UK. Their own electorate is unsure of whether it wants to be part of Europe, the long arm of United States, or a truly sovereign state.
Until UK determines what its interests are, they cannot construct a meaningful battle force that would credibly defend those interests. This is a country that has had Theresa May, Boris Johnson, and Liz Truss as national leaders. People who stand and believe in nothing. Which is perfectly mirrored in the state of their armed forces.