Hi Hotot! Welcome. Adorable bunny pic! He looks like he might be a mix of Netherland, Hotat and Rhilander. Rhinalanders though are usually larger, but the strip down his back makes me think of the typical Rhilander markings.
Thanks for the ruler reference as that is helpful to show how tiny this handsome lil’ bunny is. I understand your concerns and rabbit savvy vets will pay close attention to weight. But a rabbit savvy bunny will know how to give just the right amount of anesthesia to a bunny that has reached sexual maturity. Typically around 6 months or so. And yes, it also depends on the weight. But 3 pounds for a Netherland Dwarf is commonly okay. My very first bunny was a Netherland Dwarf. Very tiny little guy — only about two pounds. He recovered from surgery so well.
These bunnies are so lucky to have such a caring human like you. 🙂 Do you have any rabbit savvy vets near you ? Finding a rabbit savvy vet is important. Rabbits may be “common” but they have uncommon reactions that actually put them in the “Exotic” category for vet education. One of the reasons for this is because their heart rate is so fast, the vets need to trained on the best way to administer anesthesia for such a rapid heart rate. So check out this list: https://rabbit.org/vet-listings/ and check out how you find/confirm a vet that knows how to treat rabbits- – https://rabbit.org/faq-how-to-find-a-good-rabbit-vet/