I don't have time to do all of them atm, but Fiji has no 5G as far as this map says:
https://www.speedtest.net/ookla-5g-map

Yet Fiji had mortality from vaccines once they rolled out there (non beforehand).

Also no 5G in Namibia, but they saw a similar pattern to Fiji.

I don't know of a source that shows the date of installation of 5G in different areas, do you have one? I can't really look at the regions that have 5G without that info.