Adding my two cents... I spent way too many years and way too much money trying to find the perfect portrait setup. Honestly, for a first birthday, you want something that isnt gonna break the bank but still gives you that creamy background. I remember struggling with the kit lens too, it just doesnt have the wide aperture needed to blur out a messy living room. Heres what id look at for your R8:

• Canon RF 50mm f/1.8 STM is a steal. At f/1.8, you get way more light than your kit lens. Its perfect for indoor shots where space is tight.
• Canon RF 85mm f/2 Macro IS STM is the classic choice. The 85mm focal length offers better compression for flattering faces, but you have to stand further back. Personally, i think the 50mm is the smarter play for a beginner. It leaves you 400 dollars for other gear, and the optics are honestly great for the price.

Just catching up on this... honestly i was kinda disappointed with the kit lens too when i first started. Even the Canon RF 50mm f/1.8 STM that everyone loves felt a bit underwhelming for me. It is cheap but it just doesnt have that magic look you see in professional shots. Quick question tho, are you gonna be taking these pictures inside your house or at a park? Space is the big factor here. If you have the room to back up, the Canon RF 85mm f/2 Macro IS STM is definitely the winner for portraits. It blurs the background way more than the 50mm does. I actually had issues with the autofocus being a bit slow on the 85mm but for a toddler it should be fine. Since your budget is 600 bucks you can definitely afford the 85mm and its a massive step up from the kit lens. The 50mm is fine for tight spaces but it just doesnt give that creamy bokeh as easily as the longer lens does tbh.

@Reply #2 - good point! Space is the biggest hurdle when you start using primes. Since you mentioned wanting that professional look, i think the Canon RF 85mm f/2 Macro IS STM is your best bet within that $600 budget. Basically, the difference between 50mm and 85mm comes down to how much of the scene you see and how the background looks. The 85mm is more zoomed in, which creates more compression. That compression is what gives you that creamy, soft background you mentioned wanting for her birthday. On a full-frame camera like the R8, an 85mm lens is basically the gold standard for portraits. Its a decent bit more expensive than the 50mm, but you get built-in image stabilization which is huge for keeping photos sharp when a toddler is crawling around. Just keep in mind that if youre in a tiny room, youll be pinned against the wall trying to fit her in the frame. If you have the space to back up a few feet, the image quality and blur will be significantly better than the kit lens or the cheap 50mm. It just has more of that high-end feel.