Rhythmic Thump

[YarisSailor]

I've been having an issue that I can't seem to figure out the cause of yet to fix it. It's a 2010 Yaris hatchback 3dr. Manual. Just shy of 70k on it.
Anyways. Had an alignment issue for a while which I just recently got the alignment done and replaced the tires because the old ones had noticeably uneven wear (were very loud). Now that that noise they were causing is gone I can fix other issues that I'm noticing.
Anyways here's the issue:
When driving straight or turning I notice a rhythmic thumping that is speed dependent. The rhythm matches my speed, rather than being constant. Anyways it's louder at slow speeds and definitely more noticeable when rounding bends on a road at a slower speed.
Troubleshooting I've done already. 1. After new tires I noticed the thumping so I got the alignment redone. 2. Took it in for a full steering and suspension evaluation. They said everything looked fine and couldn't recreate the issue. Then had me drive with the mechanic and STILL couldn't recreate the issue. Then after I left, I heard it again. It's mostly noticeable when rounding a bend slowly, not necessarily just turning. And then when driving straight at highway speeds.
Any ideas, I've looked up the symptoms on google a million times but can't seem to find anyone who's having the same issue where the problem isn't something I've already checked.