Should We Upgrade RAM or Buy New Laptops?

I'm looking for some advice on whether to upgrade the RAM in our current laptops or to purchase new ones. We currently have HP ProBook 650 G4 and HP ProBook 400 G8 laptops, both equipped with 8 GB of RAM and running Windows 11. We use 100 laptops for students and 40 for staff. The students mainly use these for cloud-based Microsoft Office tasks and email, while staff members use them for teaching and office work.

We're considering replacing the laptops entirely with 100 new HP ProBook 460 G11 laptops with 16 GB of RAM for the students and 40 for the staff, but the cost is quite high. Alternatively, we could upgrade the RAM in our existing machines from 8 GB to 16 GB for about $200 each. My plan is to possibly upgrade around 30 student laptops and 20 staff laptops, then buy 70 new ones for students and 20 for staff to balance our budget. If you were in my shoes, what would you recommend?