I would lean towards the state legislative leader. Look at Mike Madigan for an example. Definitely depends on term limits though.
In a state without term limits? State Legislative majority leader, no question at all.
They have actual power and influence. State politics is also more appealing/less soul-crushing than national politics (Richmond and Trenton are a lot more congenial and satisfying to work in than Washington, unless you're a lobbyist).
Also unless you're in a very large state, you can go back to your regular home at night (or have short stays in hotels during session) as opposed to costly second residences in DC which everyone outside of the DC metro area has to do.
This is the first time I’ve ever seen someone describe Trenton as congenial or appealing.
Certainly wasn’t congenial in 1776
Tbf, for obvious reasons, the legislative majority leader in IL would be much more influential than in most other states.