I'm not too sure what happened, but I just noticed that there's an arrow on the left hand side of my iterm. Is this an issue with the font? If so, how can I fix it?

That triangle is painted by iTerm2. This is a part of iTerm2 Shell Integration. If you don't like it, uninstall iTerm2 Shell Integration. However, I would recommend keeping it because it's in fact very useful (e.g., there is a key shortcut to select the output of the last command, which you can then copy). There is a setting in iTerm2 preferences to disable the display of those triangles, so you can get rid of them without disabling shell integration.
Okay, so how can I remove the display of the triangle without removing shell integration? I too find it useful.
This question is not specific to powerlevel10k. If you cannot find the option in iTerm2 preferences nor in iTerm2 documentation, I'd suggest asking on a forum dedicated to iTerm2. (I'd give you the answer myself but I don't own a mac.)
Nvm found it, you can turn it off by going in to Preferences > Profiles > (your profile) > Terminal, scroll down to "Shell Integration", and turn off "Show mark indicators".
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Nvm found it, you can turn it off by going in to Preferences > Profiles > (your profile) > Terminal, scroll down to "Shell Integration", and turn off "Show mark indicators".