I have tried different installation variants. I think the installation of MicroG is not very easy because it has to become part of the system. In order for ‘Exposure Notifications’ to be enabled, all the checkboxes in the microG ‘Self-Check’ must be checked.
The easiest way for all eOS users would /e/ be to upgrade to microG Services Core version 0.2.12.203315. The discussion about this is known to the interested forum readers.
Now I have set up a Galaxy S5 (klte) with the four weeks old build e-0.11-p-2020082870302-dev-klte. It still included the microG Services Core version 0.2.10.19420.
Then TWRP Recovery installed the ‘Stable Releases’ NanoDroid-22.9.20200910.zip. The disadvantage of this method is that now a lot of apps were installed - but, after all, they are FOSS apps from the F-Droid Store. Well, every medallion has two sides. The advantage of NanoDroid is that it can be uninstalled just as easily - with the NanoDroid-uninstaller-22.9.20200910.zip
The Aurora Store was also installed. Very handy, only I had to search for a while until I found the (UK) NHS Covid-19 app version 3.6 (68).68 from 23.09.2020. In short: the Corona Warn app also works on a Galaxy S5 (klte).
Note: I haven’t done any further system tests yet, but I haven’t found any impairments. Nevertheless: Imitation please only on your own risk and at your own danger. This variant is also only intended as a temporary solution.