The kit lens that comes with the R8 is unfortunately quite subpar for indoor work because the maximum aperture is so restrictive. This is basically why your cat photos look blurry; your shutter speed is likely dropping too low to compensate for the lack of light. Given your budget, the only real option is the Canon RF 50mm f/1.8 STM. It offers a significant technical upgrade in light-gathering capability, but it is not as good as I expected in terms of build quality. I have had some issues with the autofocus motor being a bit loud and jittery compared to the higher-end L series glass. Also, the chromatic aberration is pretty noticeable when you are shooting high-contrast subjects in your garden at f/1.8. It is kind of frustrating that Canon did not include an AF/MF switch on the barrel, forcing you to use the menu or the function switch. The lens also lacks any form of weather sealing, so you should be careful using it in your garden if it is damp or dusty. Quick tip: When shooting the cat, keep your shutter speed at 1/200 or higher to freeze motion. For the garden, try stopping down to f/4 or f/5.6 to get the best sharpness out of this specific lens, as the edges are quite soft wide open. Tbh, it is a decent starter lens, but the technical compromises are definitely there.