I second this with Agoraphobic AutADHD. I desperately miss the days of flip phones and simpler IM clients. The "requirement" of having a smartphone in this day & age means that, at a low level, there is always a baseline anxiety present in me from wake to sleep.
I'm a person that needs alone time every day or I can't fully destress so knowing that anyone can always get ahold of me, or if they can't, they expect immediate responses whenever possible stresses me to holy high hell! Thankfully the friends I do have all understand this, so even if a week or a month passes between messages, it's treated like no time has passed at all. Without that, friendship is nearly impossible lol