I have been using z9 turbo for months, totally 0 notification issue. You will be surprised how far china roms have come. I have 0 notification issue on originOS.
second this. software wise still is YMMV since originOS is still CN only so some things compatibility will not be 100%, but at least over the past 4 months or so that I've been using Neo 9S Pro, it's been good for me on the whole. Before that I was using iQOO 12 with FunTouchOS and to me, OriginOS is so much better in terms of design, customisations, fluidity, etc. It's now one of my favourite Android UI, and FunTouchOS on the other hand is one of my least favourite amongst the phones I've used (and to me is considered a downside). The only thing that i like is that for Genshin at "very high" resolution, FunTouchOS on iQOO 12 uses 864p render resolution instead of 810p on CN OriginOS on both iQOO 12 and Neo 9S Pro. lol. Not sure about FunTouchOS 15 yet of course, but i doubt they will change much knowing vivo.