It's not that complicated.
Lacey is committed, so it's fair to say the staff like him a lot compared with other options. He's also a QB prospect from a region where talent rarely leaves. If you honestly think he could be your QB of the future when given the chance to take his commitment, you take it, and with it, the opportunity to influence his visits.
Russell is an ascending, in-state QB prospect with a prototype build and big arm. While he's very familiar to Sark and Milwee (from recruiting Simmons and Dakorien Moore), we already chose Lacey over Russell when the staff offered Lacey.
With that context, choosing to recruit Russell now shows they've watched his development and can more confidently project his growth into something they want to work with. He's not nearly as polished of a thrower, but Russell's ceiling is significantly higher than Lacey's, even in Sark's offense. Also, Dakorien Moore.
Imo, we sign both. If anything, the portal gives more reason to join a 2 QB class, not less. Out of high school, you can choose where you think gives you the best opportunity to be developed. When you fail to win the starting job, you find an ideal offense with an opening at QB. Literally the best of both worlds.
Even if we don't sign both, what do we lose if Lacey bounces? A generational prospect? No. The chance to land Ryan Williams? No. We lose a good QB prospect, but that's it. Choosing not to recruit Russell creates more downside risk than losing Lacey. Imagine impacting your relationships at Duncanville, Dakorien Moore, THSCA, etc over trying to keep KJ Lacey committed. Malpractice.