Edge 1040 sensor drop outs

I can‘t comment on your sensors, but as you already wrote sensor drop outs are a „well known issue“, I‘m affected with 4iiiii‘s precision 3 PM. So I don’t expect your problems to be sensor device specific. It’s either a firmware issue with the edge or worse a design specification issue with the ant+ chipset in the edge. 
There isn‘t much that we can do except for keeping our fingers crossed that it is „just“ a firmware issue which is solved hopefully not too far from now. 
Of course, Garmin‘s response policy to the problem is rubbish, they haven‘t  disclosed any technical explanations yet. 

Are you sure you have the latest SW 14.20? It started rolling out 2022-08-31, I got mine 2022-09-03 (or perhaps the day before).
I have had only a few sensor dropouts since I got mine 1040 Solar in mid July, and that was on my first tour(s), no dropouts since then. I don't have power sensors though. When I had it it was only when I paused and turned it to sleep, and when I started it again it had lost some sensors.

What / how many sensors attached may matter. One one bike I'm riding with (i) Varia radar RTL515; (ii) Garmin HRM; (iii) Garmin speed sensor; (iv) Garmin cadence sensor; and (v) Garmin Tempe (paired with Tempe Visualizer). This combination has resulted in zero sensor dropouts on the Edge 1040 but did result in occasional radar dissconnect / reconnects on the Edge 1030. On another bike I'm riding with (i) Varia radar RTL515; (ii) Garmin HRM; and (iii) a non-Garmin cadence sensor and I get a radar dissconnect / reconnect alert on average about every 5 minutes.

Perhaps work-around is to suppress alerts provided the sensor reconnects immediately after the disconnect so only if a sensor fails to reconnect then the rider is alerted.

I do have the latest software.  I have only three sensors and they are all Garmin.  I have the rally peddles (power and cadence) and I have a Garmin heart strap (heart rate), that is all.  I also made a point not to have any APPs on the edge 1040.  I check daily for updates and always install the latest.  I am at the point that I use the edge 1040 for short recovery rides, where the data does not matter, and go back to my edge 1030 for longer training rides where the data does matter.  I so much want the edge 1040 to work, Garmin fan, but I can't handle the drop outs.

Garmin Edge 1040 non-solar. I did a couple of rides with connection to Ultegra DI2 and vivoactive 4 as heart rate sensor. Working flawless. Today installed 4iiii precision 3 powermeter. Connecting, but always loosing connection after a couple of seconds. Reconnecting after maybe ten seconds. Totally useless and annoying. Connection to 4iiii is by ant+. I tested the 4iiii powermeter with cell phone app - connection with bluetooth - flawless, stable connection.

I am very disappointed. Just switched from Polar to Garmin, bought the most expensive device and it is not working as expected.

Thank you for the hint. However, the newest I can find is 14.12.

https://www8.garmin.com/support/download_details.jsp?id=15990
Do you have a link to 14.50?

14.50 is available by signing up to the beta program

forums.garmin.com/.../public-beta-14-50-is-available

Thank you for your help. Another user pointed me to Garmin Express. I have installed 14.50 beta and will check for success tomorrow.