I have around 2k USD of btc and I wanted to swap it for something but I can't decide whether to buy eth or Solana both seem extremely promising in the far future.
I will not advise you to invest in solana only or neither ethereum, but as we are entering into bullrun definitely every coin may likely have or experienced positive support, the thing is that based on the conditions of the market right as I portray before now in this thread or a similar thread, that you should split the funds and invest at least five hundred dollars worth of solana and five hundred worth of ethereum and conserved one thousand worth of bitcoin in your wallet...because what any cryptocurrency investor needs is a diversification of investment, so having different portfolio will be if advantages for cryptocurrency investor base on it's bullrun and bearish, because nobody can predict the future of Bitcoin accurately.
Both are good coins, Ethereum has a long term reputation of good trustworthiness, longevity is obviously a big positive for anything you want to invest in. There is probably more upside with Solana though, it could outperform Ethereum over the short to mid term & deliver higher ROI.
Basically if we are looking for the one that will fetch more profit during a bullrun, it will be a solana, and solana will be more productive due to it value but when you say about potential and reputation, it's ethereum, because ethereum can survive long-term duration of bearish whereas solana when bearish hits solana it will fall drastically..so as you said both are good coin to invest but when it come to potential and also a coin that can be conserved, I will choose ethereum over solana, but in terms of profit during a bullrun I will choose solana.