You have a better handle on this then our UK citizens.
To think UK can do bilateral deals with EU 27 countries is ludicrous. Why negotiate individual deals with member states with all the supporting apparatus that goes to supporting that agreement when you can have just one.
People have forgotten the original business case for the single market.
There is only WTO left which is what the rest of the World uses. As most businesses will tell you that is about the worst outcome. It'll raise costs for all businesses who will pass on as further price increases and see export of jobs.
Trade with rest of the World has geographical distance and as well as standards and the whole aspect of making / negotiating and supproting new deals. Not cheap, efficient or desirable.
But hey if the trust worthy Tories conn you into believing their tripe, knock your selves out.