I think most bourgeois class traitors come to the left of their own accord, they aren’t really convinced by anyone and we don’t need to make any effort to attract them, they are very rare anyway.
In terms of the middle class, their privelege has been a product of the material abundance brought about through Western imperialism, they are all going to be squeezed into the lower socio-economic working class in the near future, as the system continues to cannibalise itself. Really the main aim just has to be establishing class consciousness and organisation among the working class. That way there will be a pre-existing narrative for these downwardly mobile people to integrate with and understand their situation through.
It’s very hard to convince people who are materially wealthy to align with such a radical cause as Marxism. The only real avenue I could see is perhaps through presenting a very socially liberal Marxism (anti-drug war, pro individual freedoms, strongly anti-climate change, internationalist etc.), basically building Western Marxism in line with social/cultural liberal values and concerns even whilst our economic values are solidly Marxist. Basically the opposite of what class reductionists think we should do. That ought to be our strategy on an ethical level anyway, but I think the strategic value of such an approach is often underestimated.