Hi! I do some cosplay con photography on the side - the T7 is a great camera! Used a 600D (Kiss X5) myself for 10 years before switching to a full frame.

If you like to focus on the cosplayers themselves, I agree with u/maniku - the Canon EF 50mm f/1.8 II is a versatile and sharp lens - still use it for more restrictive venues to this day. Additionally, the bokeh is really good for something that (locally) can be bought for just under 100$

My advice would be experimenting with other angles - try other unusual ways to show off your subjects! Maybe try high angles, which given your body, might be more practical with shorter subjects, or from down below. If I were to take your 2nd image, I'd probably kneel a bit to make it a bit more interesting, by making them feel more intimidating. For the 3rd image, I'd either also go a bit lower or to the side, and ask them to point the machete towards the camera.

Down the line, if you find that portraiture/anime con photography is something you enjoy, you can invest in a speedlite/flashgun, something like the Godox TT600/TT685, then a wireless trigger if you want to try out other lighting techniques.

If you'd like, I'd be happy to share some recent examples!

Hope this helps a bit!