In the case of companies that have many open positions (Microsoft, etc.), I'm not sure how many of the positions to apply for. Currently I'm only applying for one at a time.
Background: I'm job searching (Senior SWE) and not getting traction anywhere -- not even getting automated rejection emails when positions are filled. Maybe I'm getting flagged as a bot? Not sure. I'm a generalist (frontend, backend, SRE, lots of languages) which is a blessing and a curse: many of the positions could be a good fit, but I'm not a perfect fit for any particular one.
Beyond that, for most companies I’m familiar with are feeding your application into a system. Submitting for a ton of roles is likely not getting you anything different than submitting for one and then having the recruiter route you to the best fit.