I got 24 slots on my multitool. After like 8hrs of flying around with this new one
I can't find a better one (with more upgrade slots). Is 24 the highest?

My understanding is yes. 24 for Multi-tool, 48 for Ship and Exosuit

Yeah, 24. I was shocked, really, to find that any single aspect of the game still required some sort of planning or prioritization. But there it was, 24 slots on the multitool. So you need to choose between min-maxing only three of the four types of devices you can build on it.

Clearly Sony and HG must be despairing over having somehow let this one challenge for the players slip past Q&A.

Here's the one I'm going with. Yes max is 24, but look is quite diversified.

Oddest thing though, it's MORE expensive to buy one with your old one's addons still in place than removed.

At least there`s a nice choice of multi-tools for everyone, from the yellow/pink to the nice gray-black ones with a strip of red.