strictly legally speaking i don't think there is any jurisdiction where you could feasibly do this. there might be some who will not give you too much shit about it but you're unlikely to be able to get decent enough fiat rails to make sense

there is of course way to incentivize better liquidity on those exchanges, specially since some of them provide api access and you can build an aggregator and essentially notify ppl where the demand is and if the price is right they might be willing to do be a one of market maker. its far from efficient operation but maybe crowdfunding liquidity on p2p exchanges is the real defi