Medicare Part C or original Medicare?

My older family member relies on me to handle anything insurance related. She has original Medicare. She also makes such a low income that Medicaid covers everything else that isn’t covered my Medicare. Just got off the phone with a representative that has offered to enroll her into a Medicare advantage plan. So many benefits that my grandmother would benefit from: hearing aid coverage, denture coverage, etc. All her doctors are covered under the medicare advantage plan as well as all her drugs. All for the added cost of $0. It just sounds too good to be true. She pays $0 in Medicare and Medicaid premiums.

We have had almost 0 issues with original Medicare.

What stuck out most to me was “prior authorizations and “run by a private company” during my conversation. My relative has numerous health conditions. Companies will always choose profits over patient care in my experience. What is the company doing to offer these benefits, but still make a profit?

Just very confuse at the moment and would like yall guidance/opinions. Thank you!