Depends on the key of the track (check out a note frequency chart). Some keys play in lower frequencies and some play higher. What's important is that your kick and sub bass don't occupy the same frequency, at least not without some good sidechain compression

True, but I myself still find it way easier if bass and kick don't occupy the same frequencies... If you ultimately are stuck in this situation somehow, I'd use a sidechained multiband compressor for the bass with a relatively narrow band located at the kick's subbass, so it just takes away the frequency from the bass that is nevertheless present because of the kick occupying the same frequency/ playing the bass in this certain moment.

Tell me what you think about this, it's probably not optimal but definitely better than clashing the whole thing.

Also, you can choose the key of the song accordingly so the deepest note in the bassline doesn't go either too high/low (I'd not go too much under 40Hz).

All the best,
Artless Venture ♢

Mine aren't simply a single sine. I like to detune it a bit and give a small amount of frequencies around 100 Hz. but no further.

And I sidechain it to the kick all the time because i want to kick to have the power that low frequencies around 40-100 Hz give.

Something similar to this.

I use a Massive patch and use two sine waves. One that will hit around the 40-50hz range and another tuned up an octave to hit at the 100-150 range. But again, no more. This is good so smaller speakers still have bass.