As with any superstar free agent, Ohtani is likely to not sign with the Giants. But I don't think it would be out of the realm either. Here are some of my thoughts on what it would take to sign him.
Also, as many of my posts goes, this went long: it is also a discussion of the positives that I see with the Giants roster and future. While the past couple of years have been disappointing, the Giants appear to me to be on the cusp of breaking out and being a serious contender for the intermediate term, if they can acquire at least one key component (a good cleanup hitter) and ideally two (another ace starter).
Lastly, I started this post thinking I needed to finish by the end of the World Series, as that was when I expected the Giants to announce their next manager. Because Bob Melvin was named manager, I finished it up and published it now, adding a note where I left the content unchanged and noting the hiring.