How is this complicated? I don't think Labour are pro-immigration. They happened to be in govt at the end of the 90s when asylum seeking claims rose dramatically as a result of the wars in the former Yugoslavia - we were part of a European agreement, initiated under the Conservatives to take people resettled from Bosnia. just as we are taking people from Ukraine atm. But this was why asylum claims went from low 100s to high thousands btw 1999 and 2003.
At the same time free movement of workers in the EU (remember it was the Tories who took us into the EU and Labour who opposed this and free movement of workers was always a condition of membership) expanded with the accession of 6 new member states in 2004.
That's why there was an increase in the numbers of both asylum claims AND workers arriving from Europe when Labour was last in power. It wasn't an active policy, but a consequence of longstanding multilateral agreements that both Conservative and Labour administrations had signed up to.
Very specifically on people smuggling - the only people in favour of people trying to cross the worlds busiest shipping lanes in inflatable boats are the people making money out of it. Everyone else thinks it is appalling and needs to end. The only differences of opinion are how not if.
If you think Rwanda was ever going to work, well I have a garden bridge to sell you...the fact it was dead in the water is why we're going to the polls next week.