> middle-income countries with comparatively flimsy Internet connectivity
Most middle-income countries I've been in had faster internet than the city I grew up in in Canada, and for about $10/mo.
Sure, internet goes down perhaps once or twice a month for half a day or so, but it often does in rural-adjacent parts of Canada too. And in middle-income countries unlimited or near-unlimited LTE phone data for tethering is also very cheap.
I never truly relied on wired internet in low-income countries, so I can't speak to those.
Unless you consider Thailand or Ukraine low income. Although my internet in Belarus and Albania was fast and reliable, and I guess those are low-income countries.