Exterior crack in foundation - patch or call a pro?

Hi all,

Just bought a 35 year old house up in New England. Had home inspection, moved in January right before a really brutal winter.

Snow and ice melted and I found this crack while working under my deck. It's about 1/8" wide and I can fit a toothpick into it at its deepest point. It's slightly obscured by the trellis, but I believe it is new since checking under the deck was part of the inspection and it wasn't noted.

I've also been told it may be at a "cold joint"? It's location is where an original foundation (basement) meets a slab foundation for an addition that was built a few years after the home. So I cannot see other side of wall.

I have zero experience with foundation crack repair. Wondering if this one is something to just patch with hydraulic cement or one of those epoxy/urethane kits and then monitor, or if I should call in a pro based on crack size, location?

I had also debated calling a structural engineer, because there is a small river at the back of the property, and I noticed some other signs that may be settling (lots of nail pops, some drywall tape seams etc) although maybe that is just cosmetic from the extreme cold this winter?

Any advice would be greatly appreciated.

Thanks!