Yes, I know... some of the new information is very sobering.
Now you know why doctors don't inform themselves about this and other topics well. They have very little chemistry and drug classes in school. And they have learned to rely on salespeople for drug info, which is not good for patients, either.

If you expose yourself to the technical stuff a little each day you will learn it eventually. Not too much at one time, as you need to sleep on it to learn it well.

And yes, you can just take both methylated B12 and folate, and see what happens. It takes time to get better though, so don't expect a fast result. Neither one of these nutrients has terrible consequences like drugs do. The only big contraindication for B12 is having a condition called polycythemia vera...which is too many red blood cells. Otherwise B12 is quite benign. Just take 800mcg of the methylfolate daily as higher doses require a prescription RX.