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Not unless you have an amazing insight / highly effective novel argument to inject into the political debate on the issue. It is an altruistic goal, but pushing for political changes that have near zero chance of actually coming to pass or have overton window shifts in the desired direction fails hard at the "Effective" part. Dont get me wrong, political action can certainly be a very effective way to do good in the world, but this particular issue is so far out of reach of the overton window it kind of isn't part of the building anymore.
The best argument I've ever been able to come up with is that we should underbid the people smuggling industry - Grant anyone who can post a 3000 dollar bond and a return ticket a temporary right of residence and employment as long as their money lasts, and I've never been able to sell anyone on it that weren't already opposed to controls on immigration.
I have also seen people much, much better at politics than me try to persuade people of the immorality of immigration restrictions. I have never seen it work. Anecdote, data, I know, but if this was a good attack angle, I should be able to think of examples of it not just abysmally failing.
If I could figure out a way to make seasteading actually profitable (iron fertilization fishing industry? ) doing that under an appropriate flag of convenience and recruiting labor out of the various hellholes people need to leave seems workable, because it doesn't require persuasion. However, it also requires what would effectively be company towns to be run to first world standards of living...
It's not an either-or thing. There are a lot of intermediate states and pushing in the direction of open immigration can be effective even if you don't expect to get to the abolisment of national borders in the near future. EU exists.