Someone mentioned in their replies on here, that this could help:
Settings - Personal Hotspot - Maximise Compatibility.
I was excited, as I thought that just maybe Apple has noticed this issue and provided a solution.
Noot!
This feature has shown up recently as it has never been there before. I have turned it on. Still the same problem persists. Not sure what this feature does in that case. Also this feature can be found on my iPhone Xs Max, however, it is not there for my iPhone SE 2016. So this magic toggle button that does nothing is probably made only for iphones that run the newest soft.
So few of my observations to make the hotspot work a little longer than usual:
1) Restart your phone, before using it as a hotspot;
2) DONT use your phone. (if you receive a message, email, any notification, be strong - do not touch your iphone. As the hotspot will be lost in 9 times out of 10)
These are quite a meaningless suggestions. Meaning - it should Just Work without any "just dont breathe" adjustments. Plus - it does not mean that your hotspot will be steady, it just gives you more chance that it wont turn on 10x in 30mins, but maybe just 5x.
For all who wonder:
1) As hotspot is turned on, it is used instantly and non-stop, so it does not turn off just because there is no activity;
2) You can keep your iphone locked or unlocked - it does not matter. It will turn off anyways.
3) It still works perfect with any Apple computers, laptops.
Imgine running your online store and adding new stuff to your store. Imgine picking out and uploading 70 images to your multiple listings.. Imgine noticing, that while images seem to be loading, your internet has been disconnected. Imgine understanding that your images wont be uploaded when you reconnect, so you have to do it all over again. And imgine this happening several times a day.
If you have stumbled upon this threat and have a similar issue, please spare a minute and press the "me too" button, or even better - write your own comment. Even if it will still say "me too". Hopefully that will gain the required attention from Apple and this issue will be fixed with iPhone69 or something..
If Apple thinks that it is most important that the connection is steady within Apple ecosystem so that customers are forced to buy only Apple products.. I dont know about you, but Id rather sell all my Apple products and buy some universally working gadgets instead.
