The UK border is literally already in Calais with infrastructure.Sorry but Calais is in France - France as a sovereign nation has control over its borders - we cannot introduce any infrastructure there.
The answer is simple
1/ like any other country allow access to the UK so they can make an asylum claim
2/ like a grown up country fund and staff the asylum claims so that people are not in overcrowded places intended for a 48 hrs stay maximum for a month or more instead
3/ when you show yourself to be a grown up responsible country use that as a starting point to negotiate repatriation agreements for the few that seem to fail in their asylum claim
Its not really that hard - but as long as we are governed by an amateurish group of clownish truth twisters who's sole way of hanging on to power is to stoke up a racists xenophobic or scared base that they are very good at doing the current rinse and repeat will continue because it suits their methodology.
Have you never travelled via the tunnel?
The rest of what you’ve said doesn’t really offer any solutions at all, in fact there’s not a single idea of what to do.