I've used nix to cross compile, and I recommend it if you can bother to learn it. It's straightforward if you want to deploy using nix/NixOS, but you can also a

I've used nix to cross compile, and I recommend it if you can bother to learn it. It's straightforward if you want to deploy using nix/NixOS, but you can also adapt it to create portable deployables. E.g. I cross-compile a mips kernel, initramfs, and small userspace to run on a system without nix. If you think your app will be ABI compatible, it may be enough to cross-compile it with nix in an ordinary way and remove the RUNPATH and dynamic linker it sets in the elf file.