I use the Suaoki 40W Solar Paddel with SunPower Panels since quite some time, and like many other brands it has raw output of up to 24V.
In the past my Xtar XP4 was able to run with it, but to run it more efficient I researched a bit and found other threads in that board and the web suggesting to use a Power Tracking Module.

Because I am not into electric modulation I wanted to find a "more or less" plug and play product - in a case - with warranty - from a commercial brand ...
Couldn't find any.
Seems like it needs to be some spare MPPT Module which is assambled but needs to get wired In and Out, which is a basic "mechanical" (not really electrical) task I can do.

Now it is about to find some great Module, the rest like a housing and the connectors I am sure able to find by my own.

Q: So may I ask if you got any experience and want to suggest your solution to get from Raw 24V to finished modulated 12V, and maybe with a buffer inside to store energy?

I found many MPPT modules just by hitting it into the web/ebay/aliexpress, and it seems like there are a ton based on BUCK Converters that might work already, but as far as me as a newbie have read up, BUCK Converters only modulate down, so every input less than the target 12V would be dropped, which is something I like to come around with a another Converter principal (a more expensive one I guess) which should have great efficiency?

Next, it was hard to find something with a "buffer" build in - one of the few self-assemble kits I could find was with Super Capacitors:

I like this idea, but the comments below the thread already have opinions that the solution is not very great because some components where used out of spec. .

All in all I would like some solution like this, capable of running up to 24V/50W Input, maybe storing like 10-20-30Wh (depending on the weight) - no fancy controls needed, as long as I can set it with a potentiometer and LC Display to my target Output:
But it looks like the road goes deeper into the topic and need you to gain enhanced knowledge about this - which is a path I would like to skip as far as possibly?