Clinton through 2001 - ended with a 1.2% GDP surplus
Bush through 2009 - ended with a 9.8% GDP deficit
Obama through 2017 - ended with a 3.4% GDP deficit
Trump through 2021 - ended with a 12.3% GDP deficit
Biden through 2025 - ended with a 5.9% GDP deficit
Trump now - running even higher, though final data isn't yet available.
There's a clear pattern available, where one party reliably leaves makes the situation worse, and the other party reliably makes the situation better. The fact that Democrats cannot undo all of the massive damage done by each Republican administration does not mean "both sides" are the same.
If you want third parties to win, they realistically need to start with local elections, so they can gain momentum and take the spot of one of the majors. (also helpful to get rid of FTTP voting in as many elections as possible).
We're seeing great success with local democratic socialists, who keep showing that government can be a force for good, it can be improved, and it can be done without blowing budgets. It's a promising start, and it's clearly threatening Dems and the GOP alike.