https://www.roadcasesusa.com/categories/Effect-Pedal-Cases/ - I have 28x14x6, it has 6" room at the side and 2.15" at the top. You might want a riser for the helix, otherwise youll have to lift up to connect XLR cables. It's 2.4" thicker than the helix, so I have some eggcrate foam in the box. Honestly, it's an excellent case, but I wish it was lighter and a bit smaller. 26x15x4 would be perfect.

Gator Cases Padded Utility Bag for Guitar Pedals, DJ Controllers, Micro Synths, and Much More; 24.5" X 11.5" x 4" - juuuuust big enough, and not very padded. Super light and compact though.

Also consider the Helix Backpack. It's a good value: lighter than a plywood case, but more protected than a soft case (it has plastic sides). Perfectly sized, has backpack straps, and an extra pocket - plus, it's nice quality. I wish I would've bought it from the start (unless someone can recommend a more protective soft case).

(The helix floor is 22.05x11.85x3.6")