Agree with Kilian Foth.

I think you should create a wrapper shell script where you can set the necessary environment variables and them run the executable after that.

Question Should the install step of a package manager modify a user's environment?

Answer No. It's a bad idea to modify a user's data, in this case the .bashrc file. User's data should be considered sacred by a package manager?

Question Should the install step of a package manager simply prompt the user to do so themselves?

Answer This is a lot more palatable solution but still not ideal.

I think you should create a wrapper shell script where you can set the necessary environment variables and them run the executable after that.