Very good point in this article that third-party cookies can be deleted but fingerprinting - like fingerprints themselves - cannot be. And quoting Google in 2019 before they decided to be even more evil than they are now.
This might be the best article I've seen about the change, and it's posted on a company blog.
Digital fingerprinting collects and analyzes multiple data points from a user’s device - such as screen resolution, installed fonts, browser settings, and even battery status - to create a unique profile
Why is all this information available in the first place? Why the hell does a website need to know which fonts are installed, which browser settings are active, and why the hell would it require the battery status? Why are browsers sharing that much information in the first place?
Because Javascript was a cancerous mistake. Web browsers should never have been scope-creeped to allow executable "apps" instead of "pages" of document markup.
I'm gonna be honest, I'm skeptical of the claims this article makes. Tuta has a history of using fake emails and "updates" from competitors in order to sell their product. Last year, they spread a screenshot on their Mastodon account of a fake email allegedly from Google, announcing that Gmail was shutting down. They were told in the post that their claim was inaccurate and that the "email" they were sharing was fake, but they left their post up anyway.
It wasn't until they were told that they could be sued for false advertisement that they removed the post. Their response was effectively "Oops, we forgot to fact-check it before going to bed", which I'm not sure I believe, because how do you write an entire post based on a screenshot, with the intention to sell your product, and not think even for half a second "Hmm maybe I should confirm some of these wild claims I'm about to make"? It's either malice or incompetence, neither of which instill trust.
I'm not saying this to defend Google, just to highlight that Tuta doesn't take issue with lying to potential customers, and that's something you should know before you give them your money. If they're willing to spread such a stupid and easily-disproven lie before you're even a customer, what are they willing to lie about once you give them your credit card?