I'll just compress the buss channels first to get it to the max level, then sidechain it to the bassdrum to give space for the two of them and then i'll lower a bit the frequencies that are alike of each one (for example i will remove 10-60 hz on the synth and then remove 150-300 on the bassdrum) it may sound weird by reading this but when you compress everything it would help removing the mess in frequencies. A tip appart from this that I was told is to remove any innecessary frequencies from every channel to leave room for instruments that really use them.