"many Brexit supporters don’t want the reality of Brexit but something else instead"
Not the way I see it. All, or most shall we say, in case someone finds a few exceptions, wanted to leave and voted to leave. None of the deals nor suggested Remainer options put forward so far has offered Brexit, and judging from EU comments it's never going to be. So those who want Brexit have to accept there is only one option and I think many realise that. No one wants something else.
Different promises are not a good argument since these groups were cross party so had no power to promise anything. Various statements on what was thought may or may not be possible, were made, but that was it. And there was no exaggeration on the scale that the remain group and it's supporters made about how awful the option they opposed would be. We already were living the issues of membership and had been for decades so many of the problems were known, and the direction that the EU was heading, clear. It was as straight as it could be expected to be.