Do you know if it is possible to use it using ledger or trezor?
No, it's not possible to use Atomicdex with hardware wallets, and even if you could do it there is a problem with low low volume and low liquidity.
If you check dexstats.info you will see that total volume for last 24h was only around $51500 or 1.12 BTC, and majority of trades are done just for KMD/TKL trading pair.
That means you can't really use Atomicdex in real life yet, and Bitcoin addresses there are still using only legacy format starting with 1.
The only downside I see in AtomicDEX is that you cannot connect your ledger nano to it.
Main downside is that nobody really uses Atomicdex.
Yes, low liquidity and the reluctance of developers to do something about it is a serious problem.
Developers created a product, but forgot about marketing, here's a product, use it however you want.
The community is in no hurry to use.
Vicious circle.