Another option that is often overlooked on here is O2 spacers. The sensors on our cars are very sensitive so the typical 90 degree bend O2 spacers will not work, which I think has given this idea a bad reputation.
I took a shot in the dark with the "mini cat" O2 spacers that appear to have a small catalytic converter in them. They've now been on my car for over 2 years (with test pipes) and the car has passed emissions twice with the secondary O2s reading ready both times. FWIW I've never had a CEL with them on.
I got the cheapest ones off Amazon, see below, but Fabspeed makes a really nice set.
https://www.amazon.ca/LEDAUT-Degree-.../dp/B01MTA6OXG