So if I understand this correctly you are creating dex exchange for trading crypto only, there is no fiat currencies available?
We already have Bisq exchange and forked HavenoDex (RetoSwap) that have both crypto and fiat trading options.
Making everything from scratch doesn't sound like a good idea when we already have something that works fine (Bisq, Haveno, Basicswap, etc.).
Right, this is not a fiat on- or off-ramp.
Bisq and HavenoDex are a pain in the ass to use. And BasicSwap? Forget about it! You have to do a bunch of crap in the command prompt, and set up a full node for any coin you're trying to trade... don't get me started on Basicswap. That sort of exchange is basically what inspired me to work on my user-friendly DEX.