Need lash advice help!

I have naturally straight, downward-pointing medium lashes with decent volume, but I struggle to maintain curl and lift. I’ve tried cluster lashes (Veyes manga set), and while they look great on day one, they start to fall flat by day two and become uncomfortable and itchy by day three or four, so I end up having to redo them frequently.

With mascara, I’m currently using Tartelette XL tubing mascara. It adds some length, but the result isn’t very noticeable and it doesn’t hold a curl, even after using a lash curler.

I’ve also tried lash extensions, but they’re quite expensive in my city, so they’re not a sustainable option for me.

I’m now considering trying a lash serum that really works but safe and free from side effects. I’d really appreciate any recommendations or advice based on your experience.