Dual-core laptop & 4 Gb of DDR2 & Mobile DX10.1 GPU (512 Mb). Of course I start the game with" ....\PillarsOfEternityII.exe" -force-d3d10" as the game "requires" a DX11 compatible GPU with 1Gb of VRAM. Also, AMD legacy drivers (13.1) from like - 2013???. And I'm in Neketaka at the moment, after 22 hours.
I tested your save and had no problems of getting to Arena Sub-Level, the same way I got there. (And Cheats / Restore = "Unity Console")
One thing might be: Page files settings. I've got the "let windows (8.1 pro) handle it" setting at the moment. Same games really don't like that (= they crash and whine about running out "memory"). In that case, I usually set it to "min 4096 / max 8192 Mb" or to a fixed size, like 16384 Mb.