I’ve ridden both my hardtails 29 and mullet. I like both.
My Middlechild Ti hardtail has a highish bb. I have ridden it with 27.5, 27.5+, mullet, and 29 (2.6) wheel – I prefer 29 overall but mullet is good fun too.
I haven’t tried my Ripmo AF in Mullet mode yet, it’s so much fun as it is :-)
I sold all my 27.5 forks about 2 years ago. 29er forks are only 10mm longer A to C. By dropping the travel 10mm you can fit them to any 27.5 bike with a 27.5 front wheel. Or just don’t drop the travel :-)