Well hard to tell tbh, every is hard if u don't have spikes around it. Corrupted dinos ain't hard to kill, enraged rexes are problem. If u got one or two in wave is ok, but if u got 4+ and if thay come near osd it's game over. Your giga will enrage 100%
On other hand with spikes is much, much easier. U can solo it with giga and snow owl, u need to heal 1 or max 2 times until u hit wave 7. With two riden giga is walk in the park, without healing wave 7.
Just to give u a bit more Infos, our gigas have 125-130 saddles, with 850 meele, imprinted 100%. When u put spikes down do it with alt character, than wait to orp to kick in.
I personally always doing purple drops on north side of map, I mean from city everything up north, near snow or near forest, south u have only few spawns and I don't like them because they are near border, so if u got a bit more lag or don't know what u can go easy outside.