I believe this is the question that should be asked;
If you believe government mandated training must be a prerequisite for a [CONSTITUTIONAL RIGHT TO BE EXERCISED], what is the curriculum you suggest?
What training should be required to vote; to exercise free speech, freedom of religion, a free press, the right to peaceably assemble, to petition the government for a redress of grievances; to keep and bear arms; to be secure in your person, house, papers and effects against unreasonable search or seizure; against double jeopardy and self incrimination; to a speedy and public trial by an impartial jury with the assistance of counsel; against excessive bail or cruel and unusual punishment; and against slavery or involuntary or involuntary servitude?
I think it is safe to say that the freedom of speech, freedom of the press and to vote allow those with no knowledge of a subject at all to speak freely and allow the press to blatantly lie and voters with no knowledge of candidates to vote. Frankly, I believe these to be the greatest threat to our republic!
As to other parts of the discussion, the initial question was specific to “mandated handgun training” so a concealed or concealable weapon would be a handgun. Since almost every hand/body carried weapon is concealable in some manner with the right smoke and mirrors, how important is the definition. I can conceal an AR, AK and shotgun, with the proper clothing, all at the same time. And let’s not forget that Warthog conceals a cannon as an airplane.
If we want to talk about flawed laws, lets look at the 1st and 2nd Amendments. The first amendment begins with “Congress shall make no law respecting …” Wouldn’t it have been nice if the second amendment said “Congress shall make no law respecting the right of the people to keep and bear arms.” How simple that would have been. But it does not! In the law, words have meaning and if different words are used they have different meanings. The people who wrote the 1st Amendment were same as those who wrote the 2nd Amendment. SO, “shall not be infringed” does not have the same meaning as “Congress shall make no law.”
If you want a real primer on the Second Amendment and the Supreme Court’s interpretation of "shall not be infringed, you really should read District of Columbia v. Heller and McDonald v. City of Chicago, Illinois.
https://www.supremecourt.gov/opinions/07pdf/07-290.pdf
https://www.supremecourt.gov/opinions/09pdf/08-1521.pdf