Remote workers in US tech companies, how much do you work?

Depends on the company, but 40 hours a week minimum is pretty common where you're actually working the majority of it. Lots of meetings too that you might not feel are actual work as coordination is challenging regardless of WFH. Some weeks I work a lot more than 40 hours (especially closing out a big project), so maybe 70+. I wouldn't work for any company where that is the norm though as they've done plenty of studies to show humans aren't meant to work at that level for long. The diminishing returns are huge. As far as vacation, I think to get what you have, you'd need like 15+ years of experience at most companies. Generally an entry level employee in tech would be lucky to get 2 weeks of vacation plus maybe a week of sick time and a few holidays. I would not recommend working on a team with on-call responsibilities. I did that for 8 years and any weekend I was on-call, would be called frequently to fix obscure problems. Between the frequency of the calls and the difficulties in finding an answer to the hours of the calls (middle of the night), to even the existential dread of getting yet another call, I just wouldn't do it. They say pay is factored into that role, but it never is in my opinion.

$100k relative to what? Most traditional engineers with engineering degrees start at like $75k to $80k, and will reach $100k with at least 5 years of experience, but can decrease that by job hopping. I think that the majority of IT jobs (especially without a STEM background) are similar, but start a bit lower. $100k is extremely good money in plenty of places in the US as you can still get a starter house for $150k in plenty of places in the American South if you're in a suburb. $100k is less awesome in some place like New York city or silicon valley. I don't think too many tech workers start at $100k in the US. That is the cream of the crop that graduate from ivy league computer science programs and go straight to work at one of the FAANG companies. I think that is the exception rather than the norm.

I am developer working for a very large 'non-tech' company; 100% WFH (even before covid because I don't live near any of the offices).

I only get 3 weeks of vacation a year - and usually have a hard time even using that; honestly if I had 5 weeks of vacation don't know what I would do with it - especially since covid has made it very undesirable to travel, so we will see once restrictions are lifted.

No one keeps track of my hours, but I easily do 60-70 hours a week, and where I work that is what gets you more money and/or promotions (Not the # of hours per per se, but the pace at which you get things done) - plenty of folks just 'coast along', but everyone knows who those people are, and they are the first fired when the budget gets cut.

Your work hours might be pegged to local time, so consider that your actual hours may end up being longer / later as a consequence.

If you're a directly-responsible individual (DRI) / team lead / manager, your hours (and compensation) should go up. Don't accept anything less than $100K USD in your local currency equivalent if you're managing employees that are making more than that in their local currency; the power dynamic is fatally skewed otherwise.

12h days are not unheard of, though you can also work shorter days if the workload is light.

I had experience in different US tech companies, as well as some European (all remote, European ones in "large" European countries).

In my experience, it depends completely on the company and the context. I worked hard (even weekends) for US companies where later in the year I barely worked (although I had to be online on Slack). So, take the step, it will be a great experience :)