Hi Pontus,
agree with all comments before.
we have lots of experience with US-guided central lines, less with peripheral (but some) and arterial lines. It is only done by doctors at our department. We use both approaches: out-of-plane and in-plane.
Regarding the canulas: we use both, most commonly we use the neoflon/venflon. but personally I think the one on the left is superior as it is a lot sharper and has less issues with not being able to puncture the skin or vessels adequately. Though my favourite is the Jelco iv. Once you use it you dont want to go back - especially in kids with thicker/tougher skin. Although it needs some practice as it does not have the "wings" of the neoflon which allows for a better grip.
We have some experience with the guidewire, it comes in handy at times, but needs some practice to handle optimally.
Although aimed at adults, I think this article has lots of good practical advice: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9886173/ or also here https://www.pocus101.com/ultrasound-guided-peripheral-iv-insertion-placement-and-access-made-easy/