Ask HN: IT vs. Tech? How best to focus career reboot?

After ten years teaching at the high school level, I am retiring from the classroom and looking for my next door to open.

Taking calls with people I know in and around the tech industry, I am looking into Sales, PM, and Customer Success roles; however, I am still considering priorities.

I have one acquaintance that is well established a large IT/Consulting/Sales company and is offering introductions/referrals to the head of their PM office and their Customer Success team.

Can anyone speak to the advantages/disadvantages of pursuing a career in large IT projects vs a more purely SAAS/B2B software company?