Hi! Are you running on a Mac? M1/M2 has terrible performance right now because it's emulating x86_64. This will be fixed eventually with an official JPackage ARM release: https://bugs.openjdk.org/browse/JDK-8310589 (and if not ready in time, I'll have to find a way to build Aarch64 binaries)
I don't have an M1/M2 to test with yet but I've heard running the desktop jar directly using an Aarch64 JVM can increase performance up to 10x. Some peeps on our Discord are exploring a solution.
I'm not happy with the performance yet, there's a lot more to do in future releases, but am generally trying to avoid premature optimisation. I expect to get performance up by 1-3 orders of magnitude before EA (this is still an Alpha!). Please watch this space, performance is important to me!!