Although my wife is not yet in the target demographic, she has little aptitude for modern technology, and you could say, technologically, that she's old before her time. She often has problems and gets anxious using the internet, smartphone apps, or even setting up the TV HDD recorder to record her Midsomer Murders and property programmes
*.
Two observations from our household regarding the OP's original questions:-
1) My wife has become more comfortable, and has fewer "it keeps flashing at me!" moments since she migrated from a Samsung Android phone to an iPhone plus iPad. The Apple user interface seems more intuitive (already mentioned by
@Bletchleyite and
@Old Yard Dog), devices "just work" without needing to spend a signiifcant amount of time customising for your own needs, and the look & feel stays consistent between devices and upgrades.
2) Much of the stress for those less relaxed around technology seems to be caused by constant upgrades and changes forced on us by the technology industries. No sooner have you become familiar with one system, user interface etc. than you're pushed to migrate to the latest and greatest upgrade.
Obviously constant changes, upgrades and churn is necessary for Big Tech and their hangers-on to keep raking in the billions, but I've found many applications passed "peak utility" a good few versions ago, and subsequent changes have been one step forward, two steps back.
In separate threads on Rail Forums, there are regular discussions of TVMs at railway stations, new designs of machine hardware and "upgrades" to the user interfaces (which invariably have significant problems). I'm sure some of the issues and stresses older and technically-challenged people will have with TVMs will be that just when they've got used to the way to select and buy their day return to town, the TOC (or their non-ticket-buying contractors in India) will come along and instal an "upgrade", with a totally different UI and ever more elaborate navigation to find the right ticket with the Senior Railcard discount. Not a problem you come across buying from the nice person in the ticket office, or the conductor on the train.
Regarding Microsoft Edge, I've been using this more and more as websites where I have accounts stop working properly with Internet Explorer. I've found Edge very stable and totally OK so far.
* - of course, I could set up recordng of the programmes for her, but as I dislike this genre of TV so much, I avoid doing this until the nagging gets turned up a notch or two.