One thing that would help us help you a lot better is you posting your kick+bass mix, and the kick and bass separately. That way we can solve the issue and tell you how we did it and what you probably were doing wrong. Otherwise we are stuck around a thousand possibilities of who knows what is your problem. I suggest you to do this so we can give you a more significant answer.
It's very hard to give specific mixing advice since there are many different possible reasons behind any given problem. I'll try to review some of the most common.
I see that you tried sidechain compression, but it ducked the bass too much. One solution here is to use sidechain compression only in the conflicting band, in the band that the kick and bass fight the most for, and leave the higher frequencies of the bass intact. You sidechain compress only the lows of the bass.
You can divide the bass in two bands, send the bands to two different tracks, and process the lows and highs separately. You can also use a plugin to do it for you. Some multiband compressors have sidechain capabilities, like Waves' C6 sidechain. Use only one band for the lows (bypass all others) and apply sidechain (it works exactly like the sidechain compression you know, it's just applied to a selective frequency band).
One very common issue with kick-bass is the lows being too loud, for either or both. Make sure you have those lows under control. Try using a shelving eq to lower them a little (for either or both), it might improve the kick-bass interaction. It's very easy to overdo the low frequencies.
Use a spectra visualizer to see what's going on with your frequency balance. Depending on your system and ears, it can be really hard to know what's going on for sure. With a spectra visualizer you can see if your lows are too loud, and other dynamics of the frequency domain. You can use another song you like as reference, and see (using spectra visualize on both the reference song and your song separately) more or less which frequency balance you want to apply to your song.
Another possible issue is the timbre of the kick or bass. Does your kick has enough click? Enough mid-lows? What about your bass? Either or both might benefit from some harmonic exciter, overdrive, or boost in some frequencies.