Congo sword ID help

[Mefidk]

Hi folks
Recently I have been expanding my horizons a bit into the Congo - a whole new world of wonderful forms But also mysteries. Here is one of mine. I wonder what opinion about the origins of this sword is?
It was sold to me as a Songye sword, and I can see that the blade shape is very like Songye swords. However, I cannot pin it down and I don't think the hilt and grip decoration suggest Songye. Here are some possibilities I considered:

Songye (claimed) . I found online pictures with no refs of similar swords but the hilts do not match. Blade form similar to three shown on WoDiMi's site. Also here for similar blade shape (different form) and similarities of grip - but different decoration.

Luba - Bastide identifies one example of this shape blade to Luba, but no central ridge. This example is very similar

Kuba - grip style and decoration very similar to Kuba Ikul swords. An example from WoDiMi's site: A Kuba Bambala Goribi sword with grip decoration and general grip form like this one. Blade different.
As far as I can deduce from my available literature, blades of this form do not seem to be Kuba (or just not in the books). The attached picture with copper blade is another Kuba Ikul from the collection of Dieter Schaffner (which I just bought and will hopefully be with me soon). The hilt similarities are strong.

On balance a hilt of this type seems to point to Kuba - but the blade form is a problem. So I wonder are there Kuba examples of swords of this form, or is it more likely a Kuba influenced people (who, Bena Lulua?). Or perhaps there other strong contenders I did not consider?

I'm sure some of the Congo experts here can steer me onto the right path.
Chris