I know right? For cropping/rotating I would often airdrop the image to my iPhone, crop and rotate there and airdrop it back to my mac. Sure, there's the Photos app that can do that just like on iPhone but it complicates the library management with importing and exporting.
As saagarjha mentioned, you can use Preview for that. Just open the image in Preview and you can crop, rotate and adjust color of an image. You can also export to different file format.
You can also rotate directly in the Finder. Right-click on an image, chose Quick Actions and then choose Rotate Left.
I wouldn’t use Preview as a primary editor but a lot of edits are simple rotate from portrait to landscape, crop out the boring parts, or adjust the exposure and Preview is a quick way to do that for a few photos. If you need to do more in depth changes or for more images, I would use one of the photo editing apps. My own favorite is Affinity Photo.