Can I use a US purchased Studio Display in Italy?

The only difference will be the power cord needed. The display is multi-voltage, and two-frequency.

Studio Display - Tech Specs - Apple Support

According to the following, the cords can be ordered for various electrical systems in various countries:

Studio Display Exploded View and Orderable Parts - Apple Support

If I am reading that document correctly, the Apple cord part number is: CI923-05156. Apple Stores in Italy probably have those cords available, too.

Adapters will work too, but that adds parts.

You can slo purchase outlet adapters to match the country you are going to. Similar to this:

https://www.amazon.com/European-Adapter-TESSAN-Outlets-International/dp/B0B27HX6P7/ref=sr_1_1_sspa?dib=eyJ2IjoiMSJ9.vNbEM9ikOyy49wN2KbAjgI9voN6v4dgXb5XsbJbP5LFvn0FMr7Qx8kTMq_CEhBoI0SDomjjrl4XbFFMbqEtOpChB26uYTzA-03OCL5cA9dobSqvF-g38Hq2JKT-A8bLghnrViMK9PdvwZ1XWJ3ZP0ym4oPuSwtqG5G_HKR5HUxSdyqrikBUD0hskDklQrZlTBcm6u8YHksNm0j2DsYD9d0fuU0NtXKMymVFBiSd3fQo.f6xj8vmdHTaELowi7jnJnoBXjgoNW5s0dBv5UsoiV78&dib_tag=se&keywords=italy%2Bpower%2Badapter&qid=1751153724&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&th=1

https://9to5mac.com/2022/03/21/apple-studio-displays-power-cable-is-removable-but-it-requires-a-special-tool/