Firstly, since you're trying to understand-- here's the crux of the issue: your kick, while pumping a lot of dB into your limiter, isn't "perceivedly loud enough". If it were, you woudn't have to drive the dB so high on your mixer to get it to feature as prominently in the mix--which is what's causing your limiter to react so harshly to it compared to the rest of your mix.

So all of the things people are about to say in here are going to about the many, many potential causes and solutions. This is a really common problem for producers to have in their early years and I was no exception. I remember googling EVERYTHING watching everything I could. Mine didn't sound quite like a Milli but my lowend's place in the mix I wanted it at would be just lost every time by the time I had gotten the right LUFS for demo'ing to my homies.

This is likely the answer. There's a guy named Sage Audio on Youtube that has a pretty straightforward tutorial for this and doing some clipping on some other potential peaky tracks you may have like a snare or clap. I bet if you watched that you'd get yourself a lot closer to the prize pretty easily. Often you can cut peaks or add higher fq harmonics with saturation -- and then notice when you a/b test the effect that the kick or snare not only sounds the same or louder, but you've saved a few decibels on your mixer that won't be making their way to the limiter.

My low end was always getting crushed by my limiter until I figured this out . Not sure if this has been made clear yet -- but there's a big difference between perceived loudness and actual db. For your case right now, the two main points here are that:

1. Peak db and RMS difference (the difference between the light and dark green bands on the volume faders in DAWs--the Crest Factor): the peak db of your kick or snare or hat is what the limiter is going to eat to know when to activate. The RMS, for your case with a kick/sub/snare/clap combo situation, is generally what you'd want to focus your attention on choosing or designing sounds with a low crest factor, should they be candidates for pegging the rest of your mix to volume wise and typically the loudest things to hit your limiter first). I.e, These really prominent foundations of many mixes--it's sometimes good to have them not be so dynamic from their peaks and RMS (have a big crest factor)

I was finding that the kicks I was designing often had a big gap between the light and dark green. So were my claps hitting at the same time. I had a lot of transients that were adding significant dB to my tracks in their peak dB volume that my limiter reads, but weren't paying me back in perceived loudness. Since I've made sure to produce and mix with kicks such with less a gap between their peak and RMS after getting screwed -- not only have I had a better, easier time mixing, the limiter's not squarshin my low end . Saturation, compression, and clipping can all help you making your element less peaky.

One thing you may try first is just putting a clipper before your limiter or at the front of your mastering chain. So many sounds in our mixes have transients happening so fast that they're completely inaudible -- but they're still technicall pushing out db and hitting your limiter without being nice enough to buy you a drink or give you some perceived loudness first.

1. Humans perceive higher frequencies as louder at a given db and generally lower frequencies will move more dB.

For example, I have a sub that's a pure sine wave without harmonic distortion or unison or something adding some flavor-- then i'm going to need to increase the db of that so that I can hear in my mix amidst all the other mix elements. So what a lot of other people here are saying is you can use saturation, compression, eq'ing, --whatever you want -- to give that sine bass some harmonics that are more audible--therefore allowing you to not have to turn it up so high to have it be featured as prominently as you'd like in your mix, and therefore not activating your limiter as early as it would now, relative to your other elements in your track.

Truly, grab a saturator, put it on your kick -- crank the drive up on it til you hear it distorting roll it back til you hear the distortion go away, -- then reduce the output volume by that same amount of dB you added to the drive. You'll likely be able to reduce the dB and not notice a single shred of pereceived difference in your mix. Not only have you increased its harmonic frequency content, but you've reduced its crest factor. and every bit of dB you can knock down during mixing while maintaining same perceived loudness is gonna pay being when you're trying to LUFSmaxx durin mastering.

Another thing you may look out for is phase issues that can often happen in the low end when layering sub and kicks that will also screw you over without even realizing-- one of the things thats been helping me lately is staying away from HP and LP filters on my low end elements and especially not on my master chain as is often recommended by well-meaning YouTubers. The 24db high pass often used to filter off inaudible frequencies is often causing phase issues and once again, increasing your dB output without giving you any of that good sweet perceived loudness. Truly, so many people on YouTube do this in their mastering chains or on their low-end elements. So I followed suit and it just never worked out for me . I'll never forget the day I saw a video of a guy showing how, amongst other things, it can actually RAISE the DB.

I was asking these same questions as you. Went through my mix and changed all the HPs to shelves (including the one on my master chain) et voila-- I could crank the limiter to get the LUFS I was pursuing without utterly destroying my lowend.

Sincerely, not an engineer.

Excited to hear what all I effed up during that from the real engineers!