For a very short summary, Canvas Fingerprinting asks your browser to draw a standard picture, and then takes a hash of the results. Different operating systems, browsers, hardware, etc... will result in slightly different images. As a result the hope is that one particular user will always have the same hash (even if, for instance, switching to an incognito window) while different users will have slightly different hashes, allowing the website to continue to track users even if they clear all their cookies.
Can you be tracked?
In practice canvas fingerprinting isn't perfect, and there probably aren't enough different combinations of "things" to uniquely identify users based on canvas fingerprinting alone. However, canvas fingerprinting is only one possible avenue to uniquely identify users, and more intelligent browser fingerprinting can be very successful in identifying users. Here is a website that actually measures how "unique" your browser configuration is, and therefore whether or not you can be tracked without cookies: https://amiunique.org/fp. You'll notice that canvas fingerprinting is something they check, but it is only one of literally dozens of data points they use to determine uniqueness.
In all likelihood you can be reliably identified and tracked without cookies. This doesn't mean that YouTube knows who you are just because Amazon does. However, (to use them as an example), it does mean that if YouTube wanted to, they could continue to track you even if you log out, clear your cookies, and switch to Incognito Mode. Note that I only use this as an example: I have no idea if YouTube or any particular service provider attempts to perform such tracking.
Finally it's worth a mention that a VPN has little bearing on this conversation. A VPN just changes your IP address, which isn't something that is typically used for tracking anyway - for many users an IP address changes frequently. Also, switching to a VPN doesn't provide you any anonymity for services you were already using, since they can continue to track you easily if you don't clear your cookies.