Im sorry as im sure this is answered but the more I read, the more confused I get with terms about splitting and replay tx's etc.

Can somebody help me understand the specific point of holding 1 btc and then having 1 btc and 1 btc2x after fork?

I understand that if I have 1 btc now and hold private key cold storage and dont transact for a few days around fork time.

But what I dont get is where the 1 btc2x is generated from?  Its not a new coin so its not pre-mined, right?

Is it basically down to me choosing to spend either the 1 btc or the 1 btc2x but not having ability to spend both of them?  This would seem to explain alot of the holes I think i have in my understanding.

After the fork, dont they have to become two seperate chains moving forward thus becoming a new altcoin?  Or am I missing something here that somehow wont turn btc2x and btc into 2 chains with 2 coin types after the fork happens?  Miners will be generating rewards on two chains causing generation of new coins on a new chain so i dont see how it would not be an altcoin after the fork occurs.

Is there a huge money risk here for a long-term btc holder that doesnt intend to stop holding?  I think the answer is no, not any more than usual volatile/high-risk of cryptocurrency.  Am I correct that I dont need to make a decision on my favored fork if Im just a long-term holder?  If some of my above understanding is right about the 1:1 coin holding then i think I simply would hold all my btc / btc2x and in 20 years, i could cashout one or the other from my 1 coin example (but not both).  Theres no decision timeline I need to worry about, right?