Linux

Figure out your mass deployment strategy and the tooling that you'll need to support it. The reason why Ubuntu and rhel are popular in these kinds of sectors is because of this tooling

I believe soon will a kid learn to install roblox、Minecraft and teach other kids ☠️

Using Linux in the university back in 2004 helped make the jump to Linux at home and I have been using it for 20 years now.

I was thinking of Pop!_OS but also heard about NixOS that could be even run on Mid-2012 MacBook Pro.

Linux has been ready for some time within various educational programs, but maybe you are referring to relatively early education curriculum in public schools? The general anecdotes I've heard from teachers within a variety of grade levels in the USA (mostly elementary and high school levels, but some doctoral engineering/scientific as well) convey that the largest hurdles to overcome are:

1. Teaching the teachers. Teachers are usually very smart and capable, but are often chronically overworked, overstressed, and underpaid for their labor. They have limited mental bandwidth in learning new tech workflows while having the added obligation of teaching these workflows to students which may be at an attention/interest deficit.
2. Challenging the status quo at the administrative level. Schools often receive incentives, grants, steep discounts, etc, for installing certain types of hardware or software packages. The software baselines of some schools are restricted at the district level; many public libraries are restricted by the city/county. Perhaps the best approach here is to install Linux as a "secondary" option (similar to how a smaller number of e.g. Macs may be installed in a computer lab comprised mostly of Windows computers) until it's more widely adopted.
3. Advocating for equivalent Linux support for popular proprietary software. This is especially true for the creative design community, such as graphic design and professional music production. Adobe is usually the target of criticism here; Linux does not currently hold enough market share to capture Adobe's attention while their patrons usually have unwavering brand loyalty or are unwilling to make any tooling/workflow compromises as to maintain their livelihood.
4. FOSS-friendly awareness campaigns. Showing people that they can remain productive while not being at the mercy of Big Tech. Not using public funds for private industry.
5. Feature parity case studies compared to proprietary options.
6. Overcoming the stereotype that Linux is only for techy people, shrouded by gatekeepers, or subject to drama/infighting.

Now I want to attend your school!

I've actually been using linux with older customers for years. It solves several problems. First, it lets them get more life out of their older machines. Second, its free. Third, the kind of malware that targets linux systems isnt really a factor for little old man on facebook. Finally, when scammers call, they cant establish credibility with my customers. They get in, remote access barely works thanks to wayland not liking their tools yet. The entire system looks different and the commands are different so they dont understand how it works but the customer does. So the scam falls apart where they try to prove they know what they are talking about because they cant use the terminal properly. It always ends the same way. My customers get suspicious and say "I'm going to call my computer guy" and the hang up.

This trick has been successful for years and my users are very happy not to have to deal with microsoft's bullshit. The fact that it confuses the hell out of scammers is just a nice bonus.

Wish I could do that when my school computers had Dos and Turbo Pascal. Ah, the good old himem.sys times. Miles better than W11.

Liberation

Is there not some kind of RMM software you could be using to install the same setup on all of them simultaneously? How about monitoring? Firewalls?