It is not that simple. From asking other team members and my own googlefu here is my understanding.
Systemd-boot would need to support it. Mixed mode support was added in May 2022. But that does not mean it works everywhere, some oddities in vendor EFI implementations exist and IMO are unlikely to ever be solved.
The kernel would need to be compiled to support mixed mode.
clr-boot-manager would need patches.
So its not as simple as enabling a config option and not realistic for users to hack around to make Solus work on 32bit efi.
Personally I do not think Solus should spend its efforts on trying to support this. We have enough to do already and do not need another test case for releases. That said this is not my decision to make and my opinion may not be shared by other team members.