IF, and that's a big IF, all you want to do is communicate efficiently around the whole school campus, and IF you don't want to rely on the radios for emergencies, then I would suggest inexpensive network radios. They operate by using either WiFi or cellular data. So without one of those two, they won't work. Here's a couple for around $60 each.
https://www.amazon.com/Walkie-Network-Smartphone-Android-KSUN/dp/B09ZHZ19YK/ref=sr_1_13?keywords=network+radio&qid=1702990251&sr=8-13&ufe=app_do%3Aamzn1.fos.18ed3cb5-28d5-4975-8bc7-93deae8f9840
https://www.amazon.com/Smartphone-Wireless-Bluetooth-Function-KSUN-ZL10/dp/B097BFQLBM/ref=sr_1_14?keywords=network+radio&qid=1702990251&sr=8-14&ufe=app_do%3Aamzn1.fos.18ed3cb5-28d5-4975-8bc7-93deae8f9840
Seems like they all use the Zello app. So another option is to just have all the teachers/faculty install Zello on their phones and use that. Totally free with no service or hardware to purchase. Once installed, a channel can be created just for the school's use. One benefit to using Zello is that no one other than those you are connecting to can monitor your communications.
Just thought it may be something for you to consider.