If you are using a Red Hat/Fedora-based distro, here are some tips on how to use the dnf tool to query your install history:

Retrieve a list of manually installed packages:

$ dnf history userinstalled

Retrieve a list of all transactions:

$ dnf history list all

List the changes in a particular transaction:

$ history list <num>

Undo/rollback a transaction:

$ dnf history undo <num>