Lately I'm trying to mix into 0 or -0.3 somewhere in-between without limiter on master doing anything. with clipping it is possible to do such thing. Basically I'm trying to hit -8 to -6 lufs without mastering chain. with Clipping I can do that easily but Don't like the waveform of exported audio, too many clips on the peaks. If audio summing with clipper stops audio at 0 why doesn't limiter do such thing but without cutting of things?

 

Limiter are cutters with an envelope so to speak, they are time based effects and can go over 0 if you allow them to while clippers are instant cutters and will never go over 0. Even with an attack on 1ms on the limiter in theory you can still go over 0 in that milisecond. If you do smooth clipping you can have some sort of mix of the two worlds. Saturate from eventide does a pretty good job on that aspect. O do brickwall limiting if that what's the song is asking to do. Or enable truepeak as Avenger just told you and you can nail -0.3 just by dialing it.
Also, does that clipped waveform sounds ok to you? What is your general vision on the mix you're making? What genre are you trying to mix? Are you following Baphometrix method? Balancing the use of clippers and limiters on the mix is a really a tought skill to master.

https://integraudio.com/clipper-vs-limiter/

 

Also, this:
(From the Pro-L manual)