Help narrowing in on solutions for international non-profit, overhauling each location network for easier remote management

Greetings!

I read the sidebar, and I've been knee deep in research for a week+ (not very long!). I'll try to keep my explanation short, but let me know what other information I can provide.

I'm taking on a new role within a non-profit, to help with the implementation of Salesforce driven processes, both in the field and in the office.

But, I'm finding that most of our locations overseas, in developing nations, have pretty bad networks. Mostly just a bunch of piggybacked cheap wireless routers.

I'm in the process of collecting data from each location, but so far its all the same. Cheap junk installed by low level techs. :D

I'm looking for a solution to implement that would allow for dual WAN, or at least mobile data as a failsafe, content filtering, throttling, and monitoring users to see who might be abusing things.

Each location has between 10-25 computers. We don't have any servers, and out total tech demand is rather low, but I'm trying to find a solution that I can deploy to each location, which could utilize some of the existing equipment (wireless APs), but allow control over the location itself.

I've seen some Meraki and Ubiquiti hardware mentioned, but I feel a bit out of my depth here. I feel confident that I can learn/manage whatever solution we narrow in on, but there are a LOT of options out there.

Also, as a non-profit, we have pretty limited funds, especially since we are pushing Salesforce pretty hard.

I think that Cisco solutions with licensing fees will be out of our budget. I'm open for any solutions, and I'm happy to research on my own, but I feel like I need some help slimming down my choices. As a ballpark, a $200-300 solution would be awesome, but I'll have to push pretty hard for that even, since we have 8 locations that have never spent more than $30 on an off-brand router.

I'm also considering an RMM to help with the overall management of the machines, and so hoping to find something that plays well with the RMM. Are there some RMM's that are more suited to what I'm trying to accomplish, where really all we would need a better router to handle some of the hardware specific issues?

Thanks! I'm happy to explain things in more detail.