Great question, take it for what it's worth...my .02
I'm 125kg just a few years into my kiting life so maybe similar timelines... I won't say you NEED to have 5 struts to accomplish your jump goals but as I frequently say, " DON'T LISTEN TO THE LITTLE PEOPLE."
They really don't have any clue no matter how well intentioned or informed their experiences.
This year I had the opportunity to ride a bunch of brands via demo's in my area - the good news is there are a ton of great kites out there but I can tell you as a bigger kiter there IS a big difference in stability with a 5 strut kite
. Full disclosure, I do have a 3 strut OR Flite 14.5m which amazingly works well for me but it's my light wind machine -
From 12m down to 7m I have a full quiver of North REBELS all from 2017. Yes, there are getting old but the direct feel and stability of these kites is unmatched and they are made for BOOSTING, so there's that. No kite is right for everyone, but as you said - a heavier rider wanting to BOOST could do much worse than a REBEL, try one and you'll see...part of why they work for peeps like us is they are EASY to BOOST meaning not the most technical but if you get speed, set your edge and pull the bar with some pop - you will go HIGH every time...100%
Best of Luck!