How would you renovate this backyard?

[Joe Black]

Hi all,

I'm a newbie investor on my first house hack. My property is basically a 3 unit with a small backyard this has an ADU in it. I'd really like to hear your feedback on how I could potentially make this a more inviting backyard space for me and my tenants.

Some key features of the yard include a raised center section approx 25'×15' and a lemon tree.

Is the raised area necessary? The brick? I look forward to hearing from you. Thanks so much.