There have been several threads on this exact subject. These threads lay out several clever solutions to accomplish exactly what you are looking for. I don’t have those threads at my fingertips, but look for rhythmic cues. That was one elegant solution. And there are other solutions that I believe involve using extra voices.
I think you will find some good ideas here:
One hint is that you don’t necessarily have to use slash regions to get that slash appearance. Some people do this with regular notes that have slashed noteheads and no stems. That gives you the ability to combine voices with each voice having a different appearance.
Personally I find the rhythmic cues solution fast, elegant, and adequate for my needs – I am flexible in how it appears. I don’t have a publisher telling me exactly how it must look. As long as the drummer can immediately make sense of it, I’m good. That solution is better than anything I have found in other programs. Hang in there. Dorico has a learning curve, but it is well worth it. Don’t be surprised if you feel you are still on the steep part of the curve 4 months into it.