@GailL1you are correct
If you have a Marketplace plan, you can keep it until your Medicare coverage starts. Find out how to end your Marketplace plan without penalty.
If you like, you can keep your Marketplace plan too. But once your Medicare Part A coverage starts, you’ll no longer be eligible for any premium tax credits or other cost savings you may be getting for your Marketplace plan. So you’d have to pay full price for the Marketplace plan.
https://www.healthcare.gov/medicare/changing-from-marketplace-to-medicare/
There is a trifecta of bad places to get advice on this topics.
One is hc.gov where your questions are fielded by $15/hour folks who are trained in how to read answers from a computer screen.
Another is volunteer organizations, like SHIP programs. Well intentioned folks who offer advice as a part-time hobby.
And then you have carriers and associations . . . where you call an 800 number, press 1 for English, leave a voice mail and wait for someone to call you back. You never talk to the same person twice and have no idea if that person is brand new or has been there 6 months.
Navigating the health care (or Medicare) maze is akin to Dante's Inferno . . . "Abandon all hope, all ye who enter here"
Good, honest advice is out there but you must use your listening skills and trust your inner voice to guide you to someone who understands your issues and knows how to give good advice.
Bark less. Wag more.