If we see bull market this year which token will be the best profit to hold. Although risk is higher of newer altcoins but older altcoins are now more dependent. Thinking that buying before the bull market will be more profitable!
Some old coins that have reputation can still be relied on, coins like ETH, BNB, SOL, and others, but some coins that were striving to survive in the past didn't worth holding because they can go backward than expectation. Moreover, exchanges native coins like MX, KCS, and others also worth holding because as long as Bitcoin price goes up, and other coins follow the suit, these coins will also move provided their respective exchanges are still active.
New projects of these days are scary, they do come with just onetime profit to their early investors and leave late and greedy investors in lost because once Bitcoin price go down, they always find it difficult to recover on time.
From the coins you mentioned I agree ethereum, BNB and solanan are worth holding while the exchange coins you mentioned MX, KCS I don't have and probably not interested. Old coins for me are always a priority especially if they are always in the top 10 coins on CMC. Bitcoin is an old coin that is always a priority because I also do long term holding.