I have limited space in my apartment to storage the filament rolls.
I've ended up with two wall rails that accept modular brackets, 3D printed “adapter” from bracket to the wooden stick, some zip ties and a few screws.

I've used Element System rails (Single slotted WALL UPRIGHT 150cm) and brackets (Pro-Bracket 25cm length) with 22m diameter wood sticks (mine are cut into 50cm lengths).
To fix printed “adapting” to the bracket I've used 2 zip ties and to fix the wood stick to the “adapter” I've used 3.5x16mm wood screw.

Design is not something fancy, It's made to work :) - feel free to remodel/use it as a starting point for your filament wall rack.

There are two designs:
V1 - those that I've used
V2 - never printed and never used (might be a better solution - dunno).

Total cost (here in Croatia) around 40 EUR.

Ive printed in PLA/PLA+, 5 walls, 25% line infill, it holds :)