Decks, Patios, Porches and Docks - Replacing Rotten 6X6 Deck Supports

Have 6x6 deck posts that were put into concrete and 18 inches below grade. They rotted...amazing ! Want replace them and have 2 questions...
1. Can I cut the old post off at the level of the concrete footer(concrete is about 18 inches below ground level) leaving what's left of the old post in the footer, drill holes in the old footer and put re-rod in to connect the old footer to a new one that I would pour on top of it. Bring the new footer about 4-5 inches above grade and then put a new post on top of the old/new footer using a plate instead of embedding the post in concrete. Digging out the existing concrete would be a huge task !!. The existing concrete is in good shape just below grade.
2. Can/should I use a metal post?
Thanks !

i believe no 1 is a viable option, but i would drill out as much old wood as possible just to keep from having rotting wood attracting termites around my house. by the way what size are the old footers?

life begins when the kids leave home and the dog dies

Thanks !
The posts are 6x6's in footers about 18x18x??deep -24x24x??deep...they look in pretty good shape, no rotten concrete. The soil is solid clay here in Virginia....
I was thinking about drilling out as much wood as possible too....