I guess they both need to compromise.
I think the major sticking point now is that the EU wants the UK to follow it's regulations forever more, or unilatteraly be punished (by tarrifs) if it diverges over time.
Now if you are the UK and your main reason for leaving is peceived sovereignty that square peg just aint going to fit.
So essentially the UK can't get a 'Canada' deal because of it's proximilty to the EU, and the perceived threat of divergence giving the UK a competative advantage.
I don't beleive Canada, or any other country with a trade deal with the EU have to be in alignment with EU regs, hence the UK frustration.
We'd be better off if they scrapped the whole thing but it's gone way too far now.