Dark matter may not exist, in fact many observations conflict with our dark matter models. IMO I just think our understanding of physics is incomplete.

This is incorrect.

Expand please? I read a book that also proposed this. If science has moved on I'd like rto know.

It's pretty close.

Only 5% of all matter is "regular" matter, and ~27% is dark matter which makes it be 85% of all mass but not of mass-energy since there is ~68% of dark energy.

It's the combination of dark matter + dark energy that makes for ~95% of the universe's total mass-energy.

Source:

https://en.wikipedia.org/wiki/Dark_matter#:~:text=In%20the%2....

It is conflating dark matter with dark energy, and counting them both together.