1. Sure. Get a non-metal crown.
2. Sure. Get white fillings instead.
3. Root Canals. Bacteria from cavities will transverse the nerve and infect the bone. Bone will literally heal after the root canal is completed (not always, sometimes leaves a scar like you said). Are you saying it is better to extract teeth rather than get a root canal? If you extract teeth, other teeth tilt, move, supraerupt, etc then you end up with a terrible bite which can lead to more lateral forces, pain, and tooth loss.
4. What do you mean "don't exist to mainstream dentists"? Dentists are all trained to remove infected tissue after extraction. But, it can be difficult or complex, in which oral surgeons would handle.
5. "Infection and bone loss around implants is so common they invented a new world for it, periimplantitis". Of course they invented a new word, implants are new. I don't get what you're saying about ligaments of the tooth. Because people still get infections around teeth, a ligament doesn't stop many, many infections of teeth

I will say, of course, treat the cause not the disease. Alkalize your body/mouth. Coconut oil. Brush/floss/mouthrinse. Can use calcium / phosphate toothpastes like MI paste, be aware of how loaded everything is with sugar, etc.

But once you get decay in the bone your tooth, I feel it should be a case-by-case basis to recommend just extracting the tooth, vs getting a root canal or implant.

1. Sure. Get a non-metal crown.
2. Sure. Get white fillings instead.
3. Root Canals. Bacteria from cavities will transverse the nerve and infect the bone. Bone will literally heal after the root canal is completed (not always, sometimes leaves a scar like you said). Are you saying it is better to extract teeth rather than get a root canal? If you extract teeth, other teeth tilt, move, supraerupt, etc then you end up with a terrible bite which can lead to more lateral forces, pain, and tooth loss.
4. What do you mean "don't exist to mainstream dentists"? Dentists are all trained to remove infected tissue after extraction. But, it can be difficult or complex, in which oral surgeons would handle.
5. "Infection and bone loss around implants is so common they invented a new world for it, periimplantitis". Of course they invented a new word, implants are new. I don't get what you're saying about ligaments of the tooth. Because people still get infections around teeth, a ligament doesn't stop many, many infections of teeth