For a long time I have disconnected my TV from WiFi, I watch the news in the morning and watch movies on the official website of public TV or on Pluto TV on the computer or via Bluetooth on TV for free and without ads. It has been clear to me for a long time that the prefix "smart...." on electronic devices is synonymous with "spy....".
You can, every product of a company which are not profit centered apart being OpenSource, by definition is way more trustworth than proprietary soft of big US companies. Proton services made it's fame because of its known reliability since a lot of years.
Yes, Vivaldi isn't fullFOSS, because 5% of the script of the unique UI is proprietary of Vivaldi, but it's 100% auditable and even moddeable by the user, they even show how to do it in its community. Edge and Chrome would fork it in the same moment when Vivaldi make it OpenSource, killing all other Chromium and Vivaldi itself. Maybe in the future it will go full OpenSource, there are still intern debates about it. The sense of OpenSource is to be capable to collaborate in new products, but with almost 100 browsers and forks in the market, this value is pretty debatable. For the user is more important the ethics of the company respect the user, in this case a european, employee-owned cooperative, which is given with a full transparency in all it's services included in the account (mail, calendar, feed, blog, the Vivaldi Mastodon instance, e2ee sync in own server, etc.).
Vivaldi, good maintaned, no calls to Google, inbuild and customizable ad and trackerblocker. If Chromium, than this one.
Every webprovider or server in the EU is forced to reveal datas of an user because an court order in a criminal investigation, with even the risk that the service will be closed, apart of high fines if they don't. If you are an criminal, it's better to message with paper and pen, otherwise they'll find you, independent which online service you use.
More suspicious than an American commercial company offering the services? Proton is not a commercial company, they really do not need to make money with their services, all they charge you is the use of servers and hosts based on a certain amount of data that you claim, in the VPN they are one of the few that offer you a use of unlimited data with a more than acceptable speed in the free version, without ads, logs and military-level encryption, the only thing is a limited number of countries in the free version (23 server in three countries).
The same with Mail or the cloud service, where space is naturally limited in the free account, but privacy is the same as in the premium account at a very high level. If you don't trust it, you are also free to host the services yourself, since they are all OpenSource.
No dark secret, Proton products are OpenSource, made by cientifics of the CERN in Swiss. They make its incommings with the premium products, serving the free ones without ads and trackings or loggings.
I use Proton services (among others) since years and i think that they are pretty trustworth with stable services and fair conditions.