If you are eyeing long-term holding Bitcoin, don't get much technical but instead, just buy at the current price. Seems you won't try taking a regular buy and sell with your Bitcoin therefore, any price is good as your entry price as you will just idle it for long.

But just a quick tip, as a newbie you shouldn't ink on your mind on the $500,000 to $1,000,000 bitcoin price target. It might possible but what matters is, you have a Bitcoin holding. There is no other way for Bitcoin but to get up. Just manage your expectations.