Another tube preamp "What should I buy" question.

I’m looking for a preamp to last me for the next 20 years - a once in a lifetime opportunity to spend big. Have a Holo Spring DAC, and will never have a turntable so linestage only. It’s to feed a Michi S5 power amp, into a pair of Cornwalls.

I’m close to pushing the button on a McIntosh MC2700. But why not the Prima Luna Evo 400 Pre? Or (and this is a wildcard) a Leben preamp? Love the idea of a Manley Neo Classic 300B but am concerned of reports of hum that the Cornwalls would only accentuate.

I know this kind of question has been asked many times before on this forum, but what’s the current view? Does anyone have an informed opinion one way or the other?