I can understand a bit both sides here.
I understand the repugnance of possibly be part of the bad, but relatively homogeneous representation of the myth in popular culture. It's less (or not at all) a problem when everyone has their own entirely different interpretation, as the reader won't by default assume one interpretation as 'the good one' when they are presented with many.
However, like was said before, mythologies evolve. And not only by being reinterpreted by totally different set of people (which always happens and is part of the construction of all mythologies), but even by the same set of people. It is likely that if you were digging further and finding people very close to the original myth, they would likely each present it a bit differently. (Personal anectdote. I married a person from India but am from a different culture. One time I went to India with my in laws and we met a few neighbours and at a time I had a question relating to mythology -more than religion ie. not a spiritual question but something more related to folk- . It ended.. in a (good humored) argument XD. they all learnt different versions. I still don't have an answer.. but it does not matter, that's what make the richness of mythologies).
In your specific case, these versions would probably be much much closer to each others than to any of the pop culture versions (both because the pop versions are so different from the base of the myth and probably because the myth is issued from a much smaller population with probably less expansion- all that being guesses, I don't actually know), so starting from that would be a good way to go IF you wanted to go for a true portrayal of the myth. But I understood it is not what you want.
If you want to write something influenced by the wendigo but you don't want it to be recognized as one, I would suggest:
- a different physical appearance than the ones commonly seen in media. Some aspects may have to be kept but make sure to not have too many of the distinctive features.
- characteristics that are either novel or coming from another creature. Everything is influenced by something already existing, there is nothing wrong about it. If the reader thinks 'this creature reminds me both of a wendigo and a whatever' this is totally fine, and if you can built a consistent new creature that really make sense with a mix of attributes from different already existing creatures, that will probably be an interesting one.
- More important: Try to think of why your creature made you think of a wendigo to begin with. What do the have in common? What is different? What characteristics of this creature do you need to keep to make the story work? What can be changed to make your creature more singular without breaking the story? What is the general environment in which your creature appear? (Can be psychological or geographical etc. Eg for geographical if it is a starvation creature appearing in a sandy desert it's less likely people will associate it to a wendigo).
Generally, keep only the characteristics that you need and develop you own for the rest. Not only it should clear your fears regarding writing a 'wrong' wendigo, but it should also help you built a more personal creature, which may be more interesting to read for the engaged reader.