Ethereum as others have said it would have been the good altcoin to invest but it is not doing well for now.
Also, I see your second option which is Ethereum as moving around a circle, as Bitcoin and Ethereum will always be moving in almost the same way. They will earn almost the same multiples of income for you or make you lose in that same magnitude as well. This is why I have Bitcoin in my arsenal and avoided Ethereum, but only invest in altcoins that do not have many similarities to Bitcoin when it comes to the way they behave during their selling and buying times. Although, I trade Bitcoin and Ethereum all the time on the futures market, but on investing them, I am so careful not to waste my time while my money is being wasted with them when other altcoins are seriously performing well. What a waste would that be.
The altcoins that I trust most is Ethereum, at the top, BNB Solana and Shiba Inu, I choose them because they're still relevant in the crypto market and I believe that they have potentials to be bullish in the alt season. Then there are other numerous projects in the market that can give profit on the short term, but investors needs to understand that investing in most of them are gambles, so DYOR.