I have Galaxy S21 Ultra 5G. Honestly, it was fast and smooth only the first day. After I installed the normal apps I use (pretty much widely popular ones, nothing crazy), it got so slow - as slow as my old Galaxy S9+. The battery life is terrible - after an hour of live creaming, it drops by a fourth! The scroll is not smooth due to the piling amount of notifications, which keep wasting resources. I'm not an Android developer, but it seems that active notifications slow down the whole phone - no idea why! Also, be that stupid to shoot a video or live stream (like I do) - you get phone calls, message noise, etc. if you forget to turn them off! Who in their right might would want notifications while they are shooting a video? Even less so - audio notifications, which ruin your video?! Not to mention, that the whole video processing power drops, and it starts skipping frames! To me, it's a huge Android design flaw - once you start shooting a video, everything should die (well, I understand the complexity, there might be background services, etc.), but with every new phone, the same issues stay, and many times I scream that I need to buy a regular camcorder and stop dealing with those who play to be mobile OS designers! For example, I'm in a Do Not Disturb mode, yet, I get notification sounds in the middle of the night! I understand that there are apps, to which I can grant access to override silent mode (like Opsgenie, for example), but I have no such apps and granted so such rights! Worst of all, Samsung disables essential apps without bothering to confirm with me. I just noticed that Google Fit is disabled because I haven't opened it - there goes all my activity tracking for months!
When will we have sane and intelligent people behind the design of a modern mobile OS at Google? Sorry to be so critical, but I've been a loyal Android user since its first device and I'm getting tired of waiting for the basics to become available. It's not getting better, just new problems keep piling up on top of the old ones!
in 2020, I have a nearly $1,500 device, which still cannot last a day and I still have to keep monitoring the battery level! And I almost do not use my phone - I just sits in my pocket 99% of the time!