If you want to run with particularly big or memory hungry files, that’s fine - you need to poke your loolwsd.xml configuration. By default we don’t limit the memory a document can consume, but we do limit load time:
<limit_load_secs desc="Maximum number of seconds to wait for a document load to succeed. 0 for unlimited." type="uint" default="100">100</limit_load_secs>
How long does it take to load in a normal LibreOffice ? perhaps doubling that would make this fly for you.