I have an old application, EagleCAD, from 2014, a 32bit app, I managed to install it on my linux (Debian based, 64bits) and it works fine, but I had to look for and install some lib manually.
How can I package all this, the bin and libs, into one that I could easily re-install on about any distro? AppImage? Flatpak? Snap?
$ ldd ./eagle
linux-gate.so.1 (0xf7ef4000)
libXrender.so.1 => /lib/i386-linux-gnu/libXrender.so.1 (0xf7ec4000)
libXrandr.so.2 => /lib/i386-linux-gnu/libXrandr.so.2 (0xf7eb5000)
libXcursor.so.1 => /lib/i386-linux-gnu/libXcursor.so.1 (0xf7ea8000)
libfreetype.so.6 => /lib/i386-linux-gnu/libfreetype.so.6 (0xf7dd8000)
libfontconfig.so.1 => /lib/i386-linux-gnu/libfontconfig.so.1 (0xf7d85000)
libXext.so.6 => /lib/i386-linux-gnu/libXext.so.6 (0xf7d6f000)
libX11.so.6 => /lib/i386-linux-gnu/libX11.so.6 (0xf7c1d000)
libdl.so.2 => /lib/i386-linux-gnu/libdl.so.2 (0xf7c18000)
libXi.so.6 => /lib/i386-linux-gnu/libXi.so.6 (0xf7c03000)
libpthread.so.0 => /lib/i386-linux-gnu/libpthread.so.0 (0xf7bfc000)
librt.so.1 => /lib/i386-linux-gnu/librt.so.1 (0xf7bf7000)
libssl.so.1.0.0 => /lib/i386-linux-gnu/libssl.so.1.0.0 (0xf7b8a000)
libcrypto.so.1.0.0 => /lib/i386-linux-gnu/libcrypto.so.1.0.0 (0xf798b000)
libstdc++.so.6 => /lib/i386-linux-gnu/libstdc++.so.6 (0xf7600000)
libm.so.6 => /lib/i386-linux-gnu/libm.so.6 (0xf7886000)
libgcc_s.so.1 => /lib/i386-linux-gnu/libgcc_s.so.1 (0xf785f000)
libc.so.6 => /lib/i386-linux-gnu/libc.so.6 (0xf7200000)
/lib/ld-linux.so.2 (0xf7ef6000)
libz.so.1 => /lib/i386-linux-gnu/libz.so.1 (0xf7842000)
libXfixes.so.3 => /lib/i386-linux-gnu/libXfixes.so.3 (0xf783a000)
libpng16.so.16 => /lib/i386-linux-gnu/libpng16.so.16 (0xf75c3000)
libbrotlidec.so.1 => /lib/i386-linux-gnu/libbrotlidec.so.1 (0xf782a000)
libexpat.so.1 => /lib/i386-linux-gnu/libexpat.so.1 (0xf7597000)
libxcb.so.1 => /lib/i386-linux-gnu/libxcb.so.1 (0xf7569000)
libbrotlicommon.so.1 => /lib/i386-linux-gnu/libbrotlicommon.so.1 (0xf7546000)
libXau.so.6 => /lib/i386-linux-gnu/libXau.so.6 (0xf7825000)
libXdmcp.so.6 => /lib/i386-linux-gnu/libXdmcp.so.6 (0xf753f000)
libbsd.so.0 => /lib/i386-linux-gnu/libbsd.so.0 (0xf7528000)
libmd.so.0 => /lib/i386-linux-gnu/libmd.so.0 (0xf7519000)
You should be aware though that distros are starting to remove 32bit support in general, as in compiling their kernels without it so it will not work for many years longer.
That's about running on 32 bit hardware, not about running 32 bit applications
No, that is about the kernel code bit-rotting for a decade or more now and nobody wanting to maintain it.