How to boot 32-bit Linux kernel on 64-bit UEFI system without CSM

I have a system on which I *have* to run a 32-bit Linux kernel, as it needs to interact with obsolete hardware which only have a 32-bit driver available. Changing the driver is not feasible. The Dell machine I am trying to accomplish this on does not have a CSM (legacy boot support) that works with internal drives. (It only has M.2 NVME internal drive slots) I installed Grub 64-bit UEFI (from an Ubuntu live disk), and it detects my "legacy" Linux instance (on the same disk, if it's important. GPT-formatted.), however when I select that 32-bit kernel from the "legacy" Linux install, Grub gives me an error: Kernel doesn't support 64-bit CPUs. Can anyone shed some light on this or point me in the right direction? I was under the impression that it was no problem for Grub to boot a different architecture kernel.