Our 2013 Crosstrek was the squirmiest car I've ever driven. (I'm an old guy, and I've driven a LOT.) I went round and round, chasing alignment, checking struts, air pressure, etc. The stock tires wore out at maybe 20,000 miles, and they were replaced with some delightful Goodyear tires from Walmart. The squirminess didn't change. The walmart tire experience was an absolute nightmare, with the first set wearing out in less than 10k miles, then the free replacement set also only lasting about 12k. All this time, of course, I just got used to the squirm. It sorta made the little car lovable, with it's own personality, dontcha know.
Next set of tires came from Costco. Spent some money and bought a set of Michelins.
No. More. Squirm.
It's like it's on freaking RAILS now.
The endless train of crappy cheap tires were totally at fault. Never again.
If I can't afford good tires, I'll stop driving.
My two cents.