Check your limiter (By ear, your synth sounds like it's going over it's own limiter), and try an automated sidechain (so that you can have more control).
If you're using Fruity Limiter to sidechain, I recommend you stop until you get a much much better grasp of it. Even for me, it's hard to create a good sidechain with that plugin, so I prefer to create Love Philter sidechains.
I'm guessing by your use of 3xOsc that you're on FL Studio; if that's the case, try using Love Philter to create a more fine-tuned sidechain.
Turn off it's filter and create a volume envelope that lasts as long as one beat (making sure the Tempo option is enabled!), then make it loop (There's an option if you click the upwards arrow) so that it's synced with the beat; so that every time the beat happens, Love Philter's gonna duck the volume for a bit.
It's less 'automatic', meaning it's not truly activated by the beat and you're going to have to enable and disable it manually and/or with automation clips, but it gives you so much more control. Play around for a while, figure out what works.
One tip for that is a lot of the time, you're best off ducking the volume entirely, but sometimes (if you still want your audio to be a tiny bit audible on the beat) you can raise that just a bit. It doesn't take much.
I've heard that others like to use playlist automation clips linked to volume, but if you do that please don't automate the mixer knob. Add a Fruity Send and automate Dry instead, so you still have control over your mixer knobs.
I hope I could help!