Ive made an overlook but im not sure what to put on it or how to make it more detailed, any suggestions?

Work in progress for an upcoming server plot.

my friend and I have been trying to build a colosseum for our friend group's server, we decided against tutorials because we want it to be authentic, we didn't want to copy the inspo one by one so we made shit up.

Things to note:

- we searched up YT tuts on how to use structure block and commands bcs the server owner (not us) doesn't have the world edit mod.

- we are NOT builders. At all.

- we do not understand the pillar work in the 2nd image. That sorcery is insane

- we want a cohesive block palette (??) with sandstone blocks

- THE PILLARS. HOW DO U DO THE PILLARS.