If you have a decent IDE, it'll offer you the ability to swap between the "old" and newer way of doing things when you encounter code written in one of the styles.

I can't say I've had any issues getting code using the new syntax through code review though. C# 14 has been out long enough that the team is familiar with much of it, and the IDE is helpful at reminding you to consider adopting new syntax. That aside though, the collection expression syntax is pretty familiar for anyone who's ever written e.g. JavaScript.