Binance is my recommendation, the exchange is very user-friendly and accepts many local currencies, unlike other exchanges that are limited.
You can always use a centralized exchange to buy your favorite coin provided you withdraw the coins from the exchange to your personal wallet.
OP is looking for an altcoin that is not listed on Binance, a possible altcoins that will pump unexpectedly which I think is really hard to find. You can use small exchange or even DEX for this one because usually those potential token started from a small exchanges first and when they finally have the opportunity to rise, they will grab it. Just be careful with the small tokens though, they usually ended up as a scam token so choose wisely.
I don't have any name exchange on my mind because I don't trade this kind of altcoins though.
But it seems that many has suggested where to buy this small cap coins, hopefully the OP knows that risk involved with this kind of coins and also the exchanges that he is going to sell. Not saying that there is a possibility of small to medium tier exchanges shutting down, but we have seen as big as FTX collapsing. And true, this kind of coins are more attracted to pump and dump groups so another thing that the OP will have to watch as well.
