@asiasiasi The UBports PDK is what you are looking for, presumably the "emulator that didn't work". There was a recent post where someone needed to make chages for it to start. It is essentially a QEMU VM with adaptations for graphics but not used often so it can break. As you already found out, Lomiri can be ran on normal Ubuntu as well in case you want to familiarize with the environment. Individual apps can be ran (and built) using clickable desktop to test if it what you want, since apps are a big part of the ecosystem.