Do you know anyone who've done this? What was it like?
A full-time software engineer job is usually 9+ hours per day. Add even a minimal commute, and you're getting maybe 4 hours sleep. That'll only work for a few weeks at most.
If you found jobs that were a genuine 7h or 8h a day, 5 days a week, with no need to ever do "over time" or whatever ... that's minimum 14h/day, an hour for commuting, an hour for eating and showering, and do all your life stuff on the weekend, and you've got 8 hours to sleep.
So I guess it could theoretically work, but why would you do that to yourself?
I think i will have 2 job offers soon, and they’re both 7hr jobs, i was thinking what could go wrong if I took both, 1 remote and 1 local with like 10min commute.
One or two years of this, could get me to 200k in savings... which i really like, but I have to see if it worth it
In one sense you would be abusing the tools of your profession. There is a common admonition that "A craftsman does not abuse his tools".
You must make your own decision, but I would never do it.
So that all said, could you pull it off for a year? Yea, you probably could, but the personal toll it will take on you will be high and the chances of you upsetting one or both is pretty high since you won't control your schedule or meeting times etc. And what happens when the remote employer has an emergent issue and you are at your other full time position, you cannot ethically use employer #1's equipment, network or bandwidth to benefit employer #2. In fact it is generally a terminating offense if you did so without their knowledge and blessing.
My recommendation is don't do it as an FTE. And even as a consultant it took a major tool on me the first couple years I had to do that while I was hiring people. But I had to build up the reserves to hire people, so it was the cost of wanting to be in business for myself.