Large flat things tend to warp. Things with sharp corners are worst.
Enclosure is really required to get good results. Keep in mind your electronics that will be inside.
I heat my enclosure to 50C, nozzle temp on my machine is 235C and bed temp is 110C. When I design a part I round the corners and add chamfers . Bed to nozzle starting distancec (Z offset) need to be correct and bed must be level .02mm off and cause issues. Adding a brim of 6 outlines spaced .02mm from the part can help to hold things down and still be removable. Not plug and play so unless you "NEED" the part to be ABS it may be better to experiment with PETG or just a more robust PLA.
Hope that helps