In the last 6 months, I bought an iPhone 11 Pro Max and a 12.9" iPad Pro.
Everything runs lightning fast on both.
The iPad Pro has excellent battery life. The Pro Max battery time is 11:54 (Galaxy S10 Plus is 12:39). For accessories, between the two of them, I bought an Apple Pencil, a cell phone case, an iPad case/stand, a bluetooth keyboard, 2 six foot charging cables, a 24W fast charger, an Apple pencil charging stand, Apple pencil case and a headphone adapter dongle.
The only accessories I bought that had Apple's name on them were the Apple Pencil and the $10 dongle. There's plenty non-Apple dongles. It just was something I saw and grabbed one while I was already picking up some things at target. So the proprietary thing has traditionally been true, but in 2020 for Apple mobile devices it mostly doesn't apply as accessories go. As for the computers, with things like upgrades of internal hardware...Well yeah there's proprietary gouging with most modern models.
I 100% agree with you though about headphone jacks and bluetooth headphones.