Yes and no. As important as Brexit is for Britain, it's an annoyance and distraction from EU perspective. In other words: Imagination and creativity bind resources and UK is not worth to spend those gravely needed sources. /1
The red lines of EU are not a relative starting position, they are absolute which is due to the political-constitutional core of EU and the power asymmetry in the EU-UK relationship. /2
A solution can therefore just evolve if they don't breach any EU red lines irrespective of UK's position. That means the basic options are very limited in any case. Obviously, details can be dealt w/ but the principles are not under any discussion. UK'll need to swallow that. /3
Remember: you neither need to like it nor tolerate it, just accept it b/c it won't change and UK needs goodwill of EU more than they need yours. Otherwise your sources (your industry & talents) are up for grabs. /4
In any case: in principle EU don't mind much whether you opt for CETA nor another already existing model. From their perspective it's questionable whether you can't afford to stick to such a model. EU's regulatory and political gravity captures UK, irrespective of it's will. /5
However, currently nothing else than two option - besides "no deal" - are possible: "wet border" (NI w/ Swiss agreement w/o FoM while rUK w/ CETA style agreement) OR EEA+, you can get something else in 5-10 yrs if UK manages it's technological "solution" (good luck!). /6
For now you are right, the backstop will be the medium term solution. Maybe some adjustments will implemented but broadly the backstop is your medium term position. UK'd start to get more comfortable, the awkward whining won't help. /7
However if you manage to find a solution respecting all red lines of EU (e.g. by this ominous technology) they will be happy to give a full CETA. I seriously doubt that this will be sufficient for UK's economy, it will probably end up in more whining and blustering. /8
But you can get it, question is if you really want it. Or if you can stand the consequences (less wealth means cuts and cuts beg the question who pays for it, don't count w/ national solidarity on this one). But other arrangements are definitely on offer - in the long run.
UK just needs to enable them, don't count w/ EU's help. UK withdraws and UK'll cover the costs - one or the other way. More interesting question's how you cover the costs w/o deepening existing divisions, that could easily cost you more than an uneasy feeling about migration. 9/9
