It depends on what you what? The surest and most stable is BTC, it could be easy x4 in the next couple of years. The most stable altcoins that are proven are ETH and BNB, these 2 coins can probably grow x10. The riskiest are the low market cap coins and the newly launched ones. They can grow x100 or even more but you can also risk losing your investment. My latest newly launched project where I spent $3,000 is now worth $10 although it might recover, it will be hard especially if its community, supporters, and investors cut their losses and left.
Even if it is only $800, you can still diversify it a little. Let's say $300 for BTC, $200 each for ETH and BNB and you can search for a low market cap coin or newly launched coin for the other $100. And you can also do a dollar-cost averaging on bitcoin.
I think the most stable is obviously tether, busd, dai and other stable coins and then followed by alts like eth and ltc. Btc on the other hand is known to be a highly volatile coin but I think many people call it the most stable is due to the fact that it never fails them. Btc can recover no matter how low its price can go. It also exist first than the others so it had lots of experience that people have witnessed even not in actual but only by looking at the chart history.
I do believe that btc can times 4 its price but for the two alts that you mention, I am sceptical about it. 10x is too high imo even though they are not that heavy as btc but they are still a good option or addition other than btc. Low market cap coins are risky yet rewarding however the op only said coins with a promising future. I think low market cap coins doesn't have that.
