Any idea how I can support crypto—>crypto swaps on my website?

I’m creating a product that has a hosted wallet and confused on how I can have a crypto to crypto swaps option. One choice is defi crypto swaps but not realistic because of gas fees, also doesn’t support a lot of big crypto blockchains. I got an institutional crypto account with an exchange but their minimums are $15 for market trades so it’s not really plausible either as it doesn’t support lower conversion amounts. The wallet supports over 15 coins so I’m not a fan of holding balances of any of these on my own accord due to price fluctuations. Any clue how these other companies are doing it? Also if anyone knows a company that provides a service like this I would appreciate it