If you use the pattern chain function, then you can play sequences of patterns. You can also real-time record into these sequences, which is awesome.
The only slight headache I have found is that any pattern you manually set to 64 steps will default back to 16 steps after you return to a previous pattern, unless you record some sequencer data into it. Luckily, this can be totally inconsequential data (for example, a single trig put into the FX track with no parameter locks at all).
To explain how this works: If you set up A1 and A2 as both 64 steps and chain them, but don’t put any sequencer data in A2, then it will go back to 16 steps as soon as the chain starts with A1. I hope Elektron fixes this behaviour as it’s a bit annoying. I may raise a support ticket about it.
As soon as you have some data in a pattern, though, the 64 steps will remain even after jumping to another pattern, and you can chain your patterns together in a big sequence (for example, A1, A2, A3, B5, C6 etc.) Make sure you understand the link between sounds, patterns and kits in order not to lose any of your sounds when you make changes.