It simply not politically realistic... at this time anyway.
The GE is about to happen, Reform are on the rise and might indeed become the official opposition. A balanced and sensible and grown up discussion is needed on immigration as a whole, not just asylum seekers.
However it's simply not going to happen until the small boats issue is solved and seen to be solved. For a majority of people in this country it's about the fact that criminals can just force people onto the mainland of the UK, at a price. It's not even smuggling (which is in essence a secret enterprise and been going on for ages) because its now done openly and dangerously and which, whether we like it or not, the majority of people in this country want this illegal route closed properly and for many forcibly, if necessary.
The opening of legal routes is the place to start, but these will be limited to people arriving from specific areas/countries and not a free-for all, the great British tradition of 'queuing' will need to be put into action on a grand scale.
At this point the proper and grown up discussion can be held, because with an ageing population and an ever lower birth rate the UK does need immigrants, including their families, to set up home here and contribute to society. Not in 'ghetto-type' settings, where they can be used as slave-labour and open to being further exploited by criminals; not just in run down parts in City centers, or old dilapidated areas of provincial towns that are already suffering from almost economic shut down, but also in the leafy suburbs, the countryside, the coastal towns etc.
The fact that Sunak believed his Rwanda scheme, might deter people, or Starmer threatening to set the SAS on the criminal gangs, means both leaders know that they have to not only talk tough, but get results, otherwise the British public will look elsewhere for solutions.... and don't you know that's just what Farage is bidding to be asked to provide (among other things, like No TV licence, No tax < £20K income . etc.), and he's prepared to wait.