My extended ender is 400x400x200 so I can't print the main base part for TQ v5. I don't know nearly anything about using CAD files and changing things. Does anyone know enough about doing this so they could alter the part to print in 2 pieces (joined with glue or something), as unexpertly marked up in the picture?

i ran into same issue and bought the ender extender for z-axis. hopefully i’ll use it besides the base print.
fyi - its a long print too. i used CHEP’s fast print Cura profile and significantly cut down the print time