Mentioning here that startups are not really obsessed by technology, at least most of them. There is this a weird mindset going around I think that technology is a 2nd class citizen. But it is depending on the startup I guess.
To get into one of the bigger companies like Zalando, contentful, N26, GetYourGuide, Klarna, Auto1, GoEuro, DeliveryHero, HelloFresh or SumUp takes more work and experience but it's completely doable. I am now at one of the companies above after 1.5 years of company experience.
Visas they will be different for wach person but for most people but if you're not under 30 and not from a western country it is a hassle
Jobs : a lot of jobs require German and the ones that don't you'd face more fierce competition which drives down the wages considerably.
Wages: on average is lower by 20-30 percent than Toronto, 50-60 percent than sf again taking these numbers out of my ass but you get the gist. Higher end more senior jobs pay even less.
Benefits and holidays: significantly better than NA you get like 30 holidays in Bavaria last time I checked
Overall if you don't have a big friend group/ family it's worth the move in my opinion the lifestyle is much more sustainable.
It can be hard to swallow at first, but when you account for lower rent, much cheaper health insurance, and far more vacation days (~20-24 by law - and no one actually expects you to be available) along with safer cities with generally higher quality of life, in my opinion it ends up being a very, very good trade off.
I moved to Amsterdam some years back (and have worked for a Berlin based company) and don't know if I could ever move back to the states.
Also, at least in the cities, everyone will be fluent in English.
If you pick city other than Amsterdam, or are willing to have a 45 min+ commute, rents should still be reasonable.
Also the rights point you bring up is pretty key, the amount of protections, safety net, and rights you get as an employee in Europe makes it so that needing to save copious amount of money in case things go sideways is not a thing.