Regarding the network logs: I couldn’t include a screenshot last time, but it looks like that over here the files are properly loaded. Firefox:
Chrome:
Safari in a brand new iOS simulator:
No idea why your Firefox refuses to download with the unsecure connection as a reason. After all, the request is via https. Are you sure it’s not a content blocker/Enhanced Tracking Protection being sensitive about the files coming from another domain? I normally would assume it would be my computer doing something out of the ordinary, but I tried this on several devices and browsers.
The network log you “shared” just mention the JS files used by Matomo, but no trace of the page view. Whereas you also said:
Matomo does track page views
Now I don’t understand how you would expect page views in the network logs 
What I meant with that Matomo does track page views is that, in Matomo I get to see visits and all the other stats that come with Matomo without MTM. Example:
Also you try to load Matomo twice (one with standard JavaScript tracking, another with MTM). […] Note that the Matomo base code is included in the MTM container
I suspected that already. Problem is that if I don’t load matomo.js separately, no visits are tracked at all. I get the point—the current setup is not as it should be. But just to get the basic stats, until I get the MTM container to work, I will load matomo.js separately.