there isnt a way to do atomic swaps without downloading a full node?
not practically.
literally hundreds of remote RPC calls would be needed. For basilisk mode it is much fewer and still there are problems. At least with basilisk connection problems, the end result is that nothing happens.
with barterDEX, if you get a connection error, you will likely lose the funds for your trade. So the consequence for a connection problem is much greater and there are a lot more requests needed.
So, while it would be possible to do, I decide against it. Just not safe. Now, if we can get some SPV wallets with a more complete set of RPC, then it would be possible. However, even bitcoin doesnt have that many SPV wallets and I havent found one with enough of the RPC (equivalent)
If somebody knows of such a SPV wallet, please let me know