Will I get an OS update when I repair my cracked iPhone screen?

Actually, Tahoe is a Mac OS, so it doesn't apply to your iPhone. Regarding your question, there's no clear guarantee that Apple will or won’t update your iOS during the repair process. It's really best to ask them directly when you go in. Sometimes they do it to ensure everything works properly after the repair.

Yeah, since your iPhone runs iOS, they might update it, especially if they need to run diagnostics after the repair. To avoid surprises, it's best to clarify your wishes directly with the store when you get there.

Most likely, if you don’t update your phone before the repair, they’ll erase and update it as part of the process. They tend to upgrade to the latest for security reasons when they hand it back to you. Just make sure to back up your data first if you want to keep anything!