If you want for the long term investment i will be advice you just go for bitcoin,the price of bitcoin is low in these days so its good opportunity to buy and hold its for long time you will be get decent profit from its in future
Even bitcoin is the best cryptocurrency i think it is better to invest now with ethereum becuse the price is more affordable and a lot of newbie here im crypto can start with ethereum and for sure they can also make a huge profit with eth in the future.
Same thing can apply with bitcoin, after reaching 20k$ the price corrections gives a lots of opportunities for someone who can wait for that height again, you can split up as we seen ETH price right now really falling, this two top crypto currency can generate huge profits when you able to buy at this level
though chances to go deeper can't be removed but if ever that the market became healthier again you will be happy with the growth of your investment.