There is one long term thing to think about when it comes to “options”… Your option 1 is already in progress. Lets say y’all succeed as planned and a hypothetical Python 3.15 is 5x faster than 3.10. Yay! 
… Then what?
Nobody’s CPU core will meaningfully get faster going forward (just as it hasn’t in the past decade), but everyone can easily have 100 cores.
When we believe we’ve hit the wall of large single threaded performance improvements, another way forward is multi-core. We’ve known this over a decade: We’re have to deal with cores eventually. Or wind up declaring ourselves at a performance dead end. I don’t expect anyone who wants maximum performance to be satisfied at “just 5x” in the end. (counterpoint: people who want maximum performance are never satisfied)
What does that mean? We’ll have to deal with free-threading or some viable alternative in the end anyways.
So the question could be seen as one of ordering if work on both at once is deemed infeasible and which factors are chosen to decide that.