I just had the complete reverse of your experiences as by chance my sister asked me to help upgrade her iPhone 8 to 13 while I am in the UK and also her Ipad 4 to latest mini, plus her friend who had a IP6 took the 8 so I also did that upgraded for her.
I thought what better time to see how far Apple had come since I last owned an Iphone as this should be a breeze as literally Apple to Apple
Well quite frankly I was shocked and contra to what we read on MR there is no way my sister who's not a complete numpty on technology could of done this and her friend with the IP6 would of been worse off.
From the start the IP8 would not scan the Apple QR code but the IPad 4 would, the transfer screwed up account passwords and other accounts whilst you waited for all apps to be downloaded from the store that never questioned you on revised permissions etc we read so much about
Endless 2 step verifications that bizarrely goes to iPad and not the iPhone or both and the extent of menu scrolling is almost exhaustive. Of course the new Apple swiping through me and my sister for days as she lost her back button
Transferred VPN settings and Apps locked up as one prevented the other from upgrading and downloading
Her bank apps were screwed up and we could get one resolved but the other needed a visit to local branch to sort, so her Apple pay and wallet was locked up for several days
Laggy apps especially on screen rotations and even though she only has few apps several these were not optimised for Ipad and no landscape mode, I did not expect this at all
I also got all her photos sorted and other files by using Onedrive so she has access to all, as her surface laptop is infrequently used now she does not run her charity
The amount of Ads and extent of subscription requests really hit me even from a simple calculator app she uses to Apple TV with add placements etc
As she had a 3 months free trial on Apple TV that was good as I OD'd on 8 episodes catch up of the foundation
but even that was buggy and often would not resume after a small break to the toilet etc
I can't say I was impressed and the whole processes was certainly no better if not worse on some counts over an Android upgrade
Still my sisters happy despite we could not get an IW7 as they are like hens teeth in UK and the IPad that comes with a charger suits her other than having to swap cables as IP13 is not USB-C like the new Ipad mini.