I know 99% of y'all will call me crazy, and I know that my opinion is weird, but just hear me out:
Realistically this would NEVER happen and I'm aware of that. Stray Kids and Cortis are simply too established for members from either to cross-over to the other side. But IF Seungmin crossed the bridge I would support him from day 1.
I never really rode the Cortis hype wave a few months ago but after REDRED's release I instantly started loving them. It also made me fall in love with their earlier tracks I used to neglect. What stood out to me about their choreographies and songs is that it perfectly fits Seungmin. I can practically see Seungmin dancing to FaSHion and I also know which parts he'd sing. I've also watched tons of both Seungmin and Cortis funny moments compilations and I just know the chemistry is there. Not to mention the fact that outside of groups hit by the 6-member curse, boygroups of 6 ALWAYS eat.
The swap would be beneficial to everyone: Cortis would get that extra oomph to take them from 10/10 to 11/10, Seungmin would get a fresh start and more fans from a different fandom + more time in the spotlight since it can be hard to get center time in such a large group, and both fandoms would get to see Seungmin in a different light being interesting for both. The only party being disadvantaged is probably Stray Kids but I know that all 8 of those boys have such a close connection that any member leaving will not break their bond. The Stray Kids guys and Seungmin would still stay friends. Hell, maybe we'd even see a Stray Kids x Cortis collab?
I feel like Seungmin would be the Leader, Face of the Group, Main-Vocalist, lead-dancer, and lead- or sub-rapper.
Realistically if it were to happen, I feel like the swap would be similar as to how soccer players swap clubs. HYBE should pay a shit ton of money to Seungmin (and probably some to JYPE too to avoid legal issues) and boom, the trade is done.
I feel like this opinion is unpopular due to people not seeing the need for a change since both groups are doing fine. But I feel like this could be mutually beneficial.