Youtube now allows to setup personalized URL for YouTube channels. This mean that your Youtube channel URL will be www.youtube.com/@yourname instead of using random number URL in previous time.
Youtube automatically reserved personalized Youtube handler URL for your channel and you can change the handler URL later. Check the following picture.
Although you can change the personalized handler URL, you should think about searchable keywords for your channel in Google. For SEO purposes, your handler URL should reflect your channel name and keywords. This mean that handles are unique URL of your Youtube channel. Check the following official YouTube video presentation about this unique handler URL.
YouTube creators can mention each other by Youtube handlers and handlers are unique way to identify creators. So your handle URL should be unique keywords of your Youtube channel name and should avoid using the opposite keywords of your Youtube channel name.
For SEO ( Search Engine Optimization) purpose, we recommend you to choose the right keywords for your Youtube handler URL.