I spent my career working in the health care industry, and have been primary care giver for family members battling cancer.
Maybe not a risk for TVHC, but there can be problems if your Doc/Hospital discontinues supporting an Advantage plan. Imagine being mid treatment in your chemo, the Doc/hospital drops your Advantage plan, and then having just 3 months to find new doc's and infusion nurses/centers to continue your treatment.
If you can afford it, best to keep your options open via Medicare.