This issue isn't affecting me THAT much (but definitely does), in my case the game loads pretty fast, BUT because I erase my save data every time I create a new survival world. But this doesn't mean it isn't happening, it's just that I could partially avoid this issue by deleting my progress. But every time I delete it and as soon as I open the game, the save file goes 964MB because of nothing.
I just disabled it a few months ago. It improved a bit, but the loading bar stills showing up occasionally.
Currently I'm not playing offline, only in a realm. I do this to avoid other issue related to the autosave feature lagging the sound and game in general. But the bar also appears in offline mode.
When played offline, flight mode helped me to play smoothly again...until the game tried to autosave. Then it all became laggy and unplayable.
I have my game storaged in a microSD Card, I'll try to move it to internal storage and see what happens.
I did what Andrew mentions, and fortunately, I am not seeing that loading screen again. My saved data was 1.8GB, so yes, the console was trying to upload that amount everytime I play, causing this "infinite" bucle.
Not sure why the saved data of Minecraft is so huge, but I hope Mojang do something about it, because it stills causing block and audio lag when the game autosaves, and we cannot disable that.
I've done something today that SEEMS to have fixed this problem; however, it isn't a workaround that anyone would want to take :'( I deleted permanently my save data from console and cloud. It seems to be related with the storage, I think (not sure) the game is accumulating the saved data of the different versions of the game. While other games (like Smash) take 100 - 300MB of storage, Minecraft was taking 1.8GB for no apparent reason, I mean, I only had 2 worlds and 4 texture packs. That is not enough to make 1.8GB. After I deleted it and make a new save data file, it takes only 577MB of space.
At the moment, I've been playing again in a local world and in airplane mode (to avoid the infinite loading screen issue) and everything seems to be good, without lag and with a smooth framerate again. I'll see how it works after some hours of play.
However, I DO NOT guarantee this works for everyone :'( so if anyone want to take the risk and do it, then this may be helpful. Always remember that, if you do this, you will lose all of your save data. You'll have to redownload your texture packs, but will lose your worlds permanently.
The same as Andrew, I've seen this happening in local worlds as much as in realms, no matter which world I'm playing in. And as I've said before, it is not necessary to be connected to a Microsoft Account to reproduce this bug. It seems that you only need to be connected to the internet, with account or not, that's why the airplane mode works so fine. Even in airplane mode, my account stills linked, and the bug doesn't happen.
In the recent days, I've been playing with what seems a workaround, at least to prevent this infinite loading screens (but block and audio lag still). I've noticed that they don't show when I play with the console in airplane mode, and if they do (which is very rare) the game doesn't get stuck as when the console is connected to internet.
I've tried to disconnect my Microsoft Account because of this, to keep my console connected while I play, but the load screen kept showing even when loged out, so I think this infinite bucle is somehow related with the internet connection and not with the account. And I gotta say that my internet is good, other games work perfectly. Idk, maybe Minecraft tries to obtain data from a server and can't reach it or something? Which is pretty odd, because it happens in local worlds, too.
It crashes with me, too. But I just wanted to report the lag that all the system has, because the crashes seem to be at random points and I wasn't able to describe them.
This is also happening to me. I'm playing on Nintendo Switch, and even with a good connection (21.4 Mbps) I receive that message at the Marketplace. I added some screenshots of it.