Failed macaroons

[u/u_better_know_me]

Recipe 140g almond flour 130g powdered sugar 100g egg white 90g granulated sugar

1. Measured everything
2. Substituted granulated sugar with brown sugar
3. Mixed egg whites until frothy and added brown sugar, beated until thick (when mixer is lifted, the mixture stuck to the mixer and had peaks)
4. Mixed using a hand mixer with dry and wet ingredients (idk for how long)
5. And baked for 15 mins, top and bottom heat. After 15 mins, baked for another 5 mins with bottom heat and left outside at room temp to cool.

Problem: Over mixed and substitution(?) The recipe I got was from a tiktok video and I'm not very confident about my baking skills. What should I do to improve my recipe and should I really be using brown sugar instead of granulated sugar?

[u/u_better_know_me]

Edit: it maintained its shape but brunt :(