But I am not a specialist of either topic (I even thought that PAE is only for x86 but learned about CONFIG_ARM_LPAE).
Right, it's LPAE on ARM. With this setting ARM CPU is switched to different mode that uses page tables in completely different format from classic ARM. Linux memory management subsystem is deeply tied into page table format, and different page table format support is implemented using multiple levels of macros, so there is currently no way to support both with single binary. Theoretically it may possible to implement multiple format support in single binary, but I don't think it will ever happen in practice (it hasn't happened for IA32 either and distributions offer separate kernels with PAE on and off).
The other kernel I was using did have it enabled, could give that a try on the gta one as well.