First, look at your needs in your actual events. Consider the cadence range and efforts you need to handle. If those include low cadence and higher effort, then you may want to include similar efforts on the trainer.
You need to be cautious and careful about implementing any low cadence, high effort work. Risk to the joints and connective tissues is real. If you go down this road, make small and careful steps to get to your goal. Avoid big jumps in the process that may well lead to injury.
Consider dropping your usual “slow” cadence 3-5 rpm for a minute or two during an interval, and then return to normal cadence. Repeat this and drop the cadence or increase the duration in manageable steps.
The other required statement in this case is that you should consider your bike’s gearing. Can you get into a lower gearing option that allows for faster cadence? It can be a good change to add more range on the low end.