Of course Solana is still good to buy, what makes Solana still worth buying because the community is strong enough to compete in the market now, then the ecosystem is also very large so it is likely that the solana ecosystem will continue to grow.
the ecosystem is at the level of etheruem in term of maturity, kamino as one of solana protocol in lending could be said already building reputation as good as AAVE it's just matters of time.
if any, solana would be the one thing that gonna replace ETH if ETH ever fall in term of rank, since ETH ETF inflow has been really bad since the past days (and yeah it's really bad literally 0 inflow yesterday) I think the chance for solana to be the one to take eth's crown will be big.
one thing that needs to be solved though, the rampant scamming in solana, the meme coin rugpull will eventually make people think of solana as scam blockchain if left untended.
that's the only thing that solana needs to fix, as of now, every defi protocol released in solana always cater really good TVL some even more than few billions.