looking for anything really that falls under DSBM doesnt NEED to be lesser known but id rather it im looking for something with a sound like Decalius.

Hopeless is a really good band that I think sounds similar to Decalius, as well as Минута Агонии! Минута Агонии has worked with Decalius before, and I think they work really well together and make some really good music.

I'm not familiar with Decalius, but I'd recommend Acedi from Denmark. At least it's very obscure, and pretty good in my opinion.
https://www.youtube.com/watch?v=_FARfToyeiE