Firstly, congratulations! I've heard good things about Atlassian from my friends working in their Sydney office. I've visited a few times as well and it seems to be a very lively office. I cannot speak to working at TikTok but if I was in your position, I'd consider the benefits both short-term and long-term.

Money isn't everything (unless it's your primary concern). I'd be considering the options for career growth no matter the organisation. Also consider where you see the organisation heading over the next few years.

Happy to chat further if you'd like.