How common are PPO plans/plans that cover out of state specialists, surgeries, etc? How hard is it to get out of state referrals approved on private insurance compared to Medicare/Medicaid?

I’m on state Medicaid and probably would be considered chronically unwell. I was told for years that out of state referrals are a pain to get approved on my insurance, yet my current neurologist got a referral to New Haven (I live in RI) approved almost within a week. I was told (or at least remember being told) that the only insurance plans that exist that cover out of state things like specialists, surgeries, and otherwise, are PPO plans, and those plans are only provided by some employers.

I’ve gotten depressed over not being able to go to hospitals outside of my state as I feel the specialists in places such as Boston may have been of better quality, and I wonder if being on private insurance would’ve made it easier to have that done years ago. Does anybody have an input on that? I’ve thought about it a lot. Is there anything I could’ve done to be seen out of state sooner?

How common are those PPO plans, or other plans that cover nationwide, and not just inside a US state? Are they very expensive for the employer to give to their employees? Is it not common for an employee to be given a PPO plan unless they work for a company that requires a lot of travel? Do most people who are employed get PPO plans? I don’t work due to my issues, so apologies, I don’t really know how it works.

What’s the reason an individual can’t get a PPO plan? If I were to pay out of pocket somehow for something like BCBS, would that not cover out of state specialists either? I’m not sure how it works. Would I still need a referral if I wanted to go to Boston for something, if I was on Rhode Island BCBS, or another insurance plan like that?