Do you have plans for a 64-bit ArcaOS?

In a word, no.

There are many reasons as to why ArcaOS is and will remain a 32-bit operating system. Mainly, ArcaOS is based on – and indeed includes at its core – 32-bit OS/2 Warp 4.52, as IBM last built it. ArcaOS has certain functions which take advantage of memory space normally outside the address range accessible by 32-bit systems utilizing Programmable Address Space (or PAE), this is not the same as actual 64-bit computing.