Just want to point out that, while it’s a mess in practice, there is a correct place for these files and the problem is that many applications ignore it. Configuration files should be written to an aptly named folder in ~/.config/ (or more precisely, in $XDG_CONFIG_HOME which is set to ~/.config/ in most systems). ~/.local/share/ (or $XDG_DATA_HOME, respectively) is for user data, which is different from config.

Not exactly what you are looking for, but modern shells like fish or zsh (probably?) are good at suggesting completions from history. fzf is another great tool for that. Both are super useful for remembering and repeating commands.

Snapper assumes that your system is “formatted with btrfs or some other snapper compatible filesystem”. I’m pretty sure that this means that that your root directory is mounted from a btrfs subvolume.

So all you need to do is setup btrfs at install time and then configure Snapper. You should consider mounting /home from its own subvolume. That way you can roll back the system but keep all your files.

There are a lot of other things to consider when setting up btrfs, so make sure you read the docs. (A lot of the config can changed at a later point.)