I will advise you to choose bitcoin because the stage it's now is going to continue going up apart from that I have good belive bitcoin will not come down below 20k now and even though it goes below that it still has hope more than the alt Coin you are talking about.
I don't think Op has any intentions of investing in an altcoin, and since he also admitted the he lacks the knowledge to analyse what direction the market of a coin will move it will be very risky for Op to go for any other coins and most especially now that he's looking to hold for a long period of time.
It's possible for Bitcoin to go below 20k and trust me so many people are praying for it to happen so that they can accumulate more Bitcoin while others just want the price to keep increasing till it gets to its all time high again.