What are the biggest problems when exposing services?

Ciao/Hello IHs!
Recently i have been working on some side-projects regarding services exposure and web protection using L7 proxying.

I wanted to ask the IH community what are the biggest problems/pains when dealing with services exposure and protecting their applications from attackers.

I also wanted to make about this post in order to knowledge-share what are you using in order to expose your service on L7 (Cloudflare, AWS LB or direct EC2, BunnyCDN and so on...)

Feel free to add more topics into the conversation because could be useful to everyone interested into tackling CDN/DDoS/L7 issues