As many have noted, these are excellent photographs. I have limited knowledge and experience with photography. Do you worry about your work being stolen and sold?
I used to, but not so much these days. I'm not really interested in commercialising my photography (it's a LOT of work and its hard to make a decent living from) and I generally don't mind people sharing them non-commercially. Commercial use is a different matter and I do keep a bit of an eye on it (https://pixsy.com/ is great for this), but in my experience it is rare for them to get used inappropriately without being asked permission first. I also don't put them online at high enough a resolution to be useful for printing which cuts down any offline abuse.
The story you linked is an interesting one, especially given how heavy handed Getty are when it comes to misuse of any of their images in the reverse situation. Personally I think what Getty have done here is completely unethical but given the public domain nature of the images in question they might be in the clear here.
I'm an amateur photographer and, unfortunately, you see this come up a lot in photography communities online, but you don't hear about most cases in the media. You'd be surprised how many businesses will just openly steal images from any website or social media platform and use them without notice, credit, or payment. Unfortunately watermarks are either easily cropped out or they ruin the picture (like by spanning the whole image with transparent text). There are some resources for the little guy like Pixsy[0] but reports of their efficacy are mixed.
The usual advice if you find your image being used without permission is to ask the offender nicely, send them an invoice, or get a lawyer involved, depending on how far you want to take it.
I'm thinking particularly of this story: https://petapixel.com/2016/07/27/photographer-suing-getty-im...