It's not Shimo.
This is an unused Toho kaiju from Godzilla's Heisei era. It was a direct inspiration for the director to create Shimo in the new Godzilla X Kong movie. There is rare footage of him being tested on set, but was never used in a finalized movie. I loved the design so much that I had to make it for myself, since i can't buy the figure anywhere. Here's some reference images just cause he's cool.
If you want to see the full tootage, you can check out kaijushitposting on instagram. I haven't been able to find the video anywhere else.