I would like to suggest that kernel support for IA32 Emulation support be enabled.   This would allow docker that need 32 bit emulation enabled in the kernel to run.  No packages or libraries need to be added to the unRaid operating system.  If the docker has a copy of the 32 bit libraries and IA32 is enabled in the kernel the 32 bit binary inside the docker will execute.   I have tested this on an unRaid 6.3 slackware64 VM with the results of the steps and test result locate