Castle? 
Sorry, can’t resist 
Impressive number - did you ever face blue pulse of death ? [APP] Fibaro - Your home is your castle (by Athom) - #861 by Sharkys
The reason I’m asking, I have only 9 units, had to replace about 6 of them already.
Hm, energy reports should not be really an issue (in terms of "bandwidth), what do you see on Homey Developer Tools, ideally right after Homey restart and manipulating all shutters ? Maybe some of the unit is flooding the ZWAVE mesh… compare the RX values, they should be almost the same, mainly if they are operated same time. I know however from other users, they complain about responsiveness of their ZWAVE as well. You might be interested also about [HOW-TO][Pro][Cloud] - Z-Wave Route map - understanding your mesh routing may discover potentially weak spot (eg. one unit being used in all routing, because of Homey or any other router being too far away)
Btw, even manual confirms my thought - Power report are sent no often then every 30 seconds.
https://manuals.fibaro.com/wp-content/uploads/2018/12/FGR-223-EN-T-v1.2.pdf - page 29
Side note - I’m using energy measurement to check if any of the blinds are stuck because of whatever reason / eg. too high consumption then usual (in my case about 90W) → reporting issue (unfortunately there is no STOP option).
That setting works for me (for opposite effect, enabling periodic reports, report device power usage etc.), the structure is correct, maybe I would try to apply only part of it - eg. 61,2,0
Also I have completely the same firmware versions on my FGR-223 like you. How your insights look like for particular device, when you are operating unit ? For me sometimes it’s so short I see even no value reported at all…
