may seem obvious but is the core sound the actual sound you want to begin with? trying to make a thick and deep bass using EQ, compression or any other tool isnt going to work if the original sound isnt anywhere near in the first place.
id suggest re-assessing your synth/recording techniques first then move from there.
secondly, if you cant get it loud enough without clipping, might seem obvious but turn down everything else relative to it. with DAW theres a fixed ceiling you cant go above so really you need to think of headroom in negative terms with the loudest sounds near the roof and everything else working its way down.
if the overall level on the 2buss isnt loud enough, then thats why youve a volume control on your amp...use it. you shouldnt mix with a thought to final volume/loudness at all. this comes once its all done and sounding great.