I recently spent a few days troubleshooting a brand new Mac mini with a flickering monitor. I swapped monitors, cables, etc. and finally wiped the drive and reinstalled BS. That “fixed” the problem for a day and then I installed 11.3, and the problem returned. Turned out flickering external monitors is not that uncommon with M1 Macs. Eventually the mini was returned to Apple for a refund.
Only wading in here to add an observation about my holding out on the upgrade to Big Sur:
I am by no means a long time macOS user, having only come on board with OSX Lion (2011-2012?), but this is the longest I have waited prior to taking the upgrade plunge.
What I now realise, and this is mildly troubling, is that I can remember I had some fairly good reasons based on software compatibility, about why I needed to wait. At least, I think they were software compatibility issues, since, I now can’t remember what they actually were, anymore… 
So, whilst I still have a nagging feeling about it, I guess I might as well take the plunge in the next few weeks or so… Or at least before the next WWDC!
My takeaway: Next time I have doubts, I might actually make a note to my future self about what those concerns are… you know, for this very occasion.
I had these doubts with Catalina as well - I always upgrade one test mac (usually, my server) pretty quickly, but then wait with my “production” machines until the night of the Oscars. I did upgrade our personal Macs during Oscar night in 2020, but I did not upgrade my work MBP until late September right before Big Sur came out. Similarly to you, I do not remember why I held out, but there was a reason.
1 Like
Pure curiosity - do you do this because you (or somebody in your family) watches the Oscars, and it gives you something to do in the background?
Or is it just a convenient date-related reminder event for you?
Actually, both. Also, Apple has typically released at least a .2 release at that time, so the most obvious bugs are supposed to be squashed.
I can comfirm that I’ve tried two monitors from different manufacturers with my M1, and they both flicker the same (and not on my other Macs).
1 Like
Because the problem was “fixed” and came back with v11.3 I’m 97% sure it’s a Big Sur problem. 
Not this time… 
Same here. I waited until Big Sur was released before I upgraded to Catalina. Frankly, it was a disaster. I also had regular kernel panics, for some odd reason it always happened whenever I plugged a monitor in through USB C.
I had Catalina on my machine for less than a week before I moved to BS, which has been rock solid for me, on both a late 2014 iMac and a 2015 MacBook . It is also solid on my new M1 Mac mini, but I have only had it for a few days - and I love it.
1 Like
An update from me. I was getting fed up with the bluetooth issues so decided to nuke and pave.
Since I’ve done that had no bluetooth issues and performance is much better.
Also Soulver isn’t crashing anymore.
Very happy with it now 
6 Likes
Big Sur works for me. m1 air. prior to that, mid 2015 mb pro.
I live and die on these machines. no issues [meaning, whatever I encountered was remedied/dealt with with no drama].
I wouldn’t take a window’s machine even if I got it in the divorce. yeah, I know. drama.
That’s of course perfect. And I’m happy for you.
Personally though BS on my 2017 MBP is the worst experience with Apple computers since, well, probably since I used one of these Macintosh clones. Only this morning I had to reboot 4 times. For different reasons. And after each reboot I had to hope and pray my network connection was working (which it wasn’t in 50% of the time).
I can see how upsetting that is, but maybe it isn’t Big Sur. I have been running it on my 2016 MBP for a few months and have not had a crash and also on my 27 inch iMac since January without issue.
Maybe something got corrupted on your system and a clean install world resolve it?
2 Likes
A clean install is easier said than done. To do it properly, one has to install all apps from scratch and set all preferences by hand. That’s more than just a couple of hours work.
And the result of all this is doubtful too.
Based on the reports I read, chances are this is Big Sur. To be more precise, it all began when Apple started to play with the USB functionality (in 11.2.x).
Are you using wired ethernet (via a dock) on your MBP? Cause that seems to make a huge difference in the perception if the OS.
I am not using wired Ethernet on my MBP, just WiFi.
Today I tested it wirth a clean instlal on my 13" macbook pro 2015. Forget it. Even in this state it is heavyily slow.
I upgraded to Catalina just before WWDC last year and to Big Sur about a week ago, after trying out both on external SSDs right after the betas came out.
With Catalina I had continual issues getting my 1st gen Airpods to connect - always had to forget them, reset them and essentially start over, maybe deleting plists and resetting the Bluetooth module as well. The same Airpods work fine with my iPhone. Apart from this, no issues with Catalina.
With Big Sur, the Airpods have been working fine. However I’m experiencing the mouse cursor disappearing when I watch a video full screen. I have seen others report this but not confined to Big Sur. Others suggest doing gestures with Mission Control will get the mouse cursor to come back. I found command tab does it.
Are you using a USB dock or Thunderbolt?
Upgraded from Mojave when all my work apps updated to 64 bit a few weeks back and, touch wood, have had absolutely no problems.
2 Likes
I’m using a thunderbolt dock. The Belkin one.
Ethernet is recognized only after a restart and/or unplugging the dock. That started with 11.2 or 11.2.1.