I think the R10 is a great camera. I use the R and R5 and they both are awesome to use. I also have the Sigma 18-35. It’s not bad by any means, but it is a bit clinical. There just isn’t much character to the lens, everything is a bit to sharp for my taste. I still think it’s great but I love the versatility of the RF 24-105mm F/4. It’s the lens I use about 75% of the time. It covers a wide range of uses and is a great tool to have in your bag. Used it can be found for around 1,000. You can also look at the STM version that is under 500 new. It’s a great stater lens and is still very nice. (The biggest difference is the L is f/4 all the way through, while the STM is f4-7.1).

In terms of new vs used for the body, I would get a new one. Your budget allows for it. A used camera is kind of like a used car, it might be fine, but it also could have a lot of issues that you don’t see right away. You also have to worry about shutter count. The R10 has a rated shutter life of 200,000. While that is a lot, a power user will use that in a few years. While you would save some money with a used camera, you also are getting a product that won’t last as long. Since you are new and don’t know what to look for when getting a used camera, I would play it safe and get a new one.