The vast majority of libraries packaged in Debian do not include .a files. It sounds to me like your real issue is that you are attempting to use newer libraries on a distro that doesn't provide those libraries. You have some additional options beyond the workaround you implemented:
- Encourage your users to switch to Snap or Flatpak for much easier dependency handling for older distros. This is what Canonical did with Firefox, Chromium, and Thunderbird - Also package the libraries you need in a PPA or similar repository. This is a bit more complex to handle the initial user install. You're also responsible for providing security support for the library. Hopefully, it doesn't interact badly with the rest of the system. It could cause users difficulties on upgrading to new versions of their OS. Thank you, Jeremy Bícha