Hey there, welcome to the inZOI forum!
Since you’re using the ROG Ally, I think the crashes you’re describing are happening because of the handheld’s “low” 16 GB RAM.
InZOI has terrible (V)RAM spikes throughout various of its core systems atm. We’ve discussed and even captured those in this thread: Do you have such performance spikes to when entering build/ photo / map mode?.
Create-A-Zoi is a closed off space which is why your setup can handle it. As soon as another system comes in, such as world and save file generating (including: compiling shaders, world streaming, animation blueprints, texture pools, NPC-AI-states, simulation data, etc.), your setup closes the process because it’s too much to handle all at once.
→ Most likely, the main cause is 16 GB RAM (meets requirements, but not way above) which are used by your whole setup. PC / gaming laptops and similar setups have a so-called “dedicated VRAM”, which can take a lot of spikes due to very different distribution.
Maybe we have some other users here who are using handhelds too and can offer help? Even though I assume that’s quite risky with a very rough, early access title like this.