Stay away from anything SIG except the 320 and maybe the SP2022. The P-series pistols (p226, p229 etc) are Right hand biased due to non-swappable mag release and decocking lever (The mag release on the SP022 is reverse able, but the slide release and decocker are not..... probably not the best option)
I’m 100% lefty and I own a P226, an SP2022 (and now a P365!).
Not once have I had a problem with either the mag releases, the decocker or the slide release on the P226 and SP2022.
There aren’t a whole lot of guns that are set up ambi. I’ve learned to use my middle finger on the mag release and my index finger on the decocker and slide release. It’s become habit.
I recently picked up by SILs M&P 9c that’s set up lefty and it bothered the hell out of me. I want all my guns to be set up the same, so it’s natural no matter what gun I pick up. Having some one way and more another is confusing. I don’t mind an ambi safety, but everything else on my guns is set up for a righty.