@letterus @agx Most of apps you're likely to run under phosh (and also phosh itself) is still based on GTK3, and GTK3 is purely software rendered - PinePhone's slow memory bandwidth is a huge bottleneck there. It is noticeably snappier on the Librem 5 since its RAM is significantly faster.
One thing to check is whether arm64 optimizations are enabled in pixman build used by your distro, there is a patch that's not merged upstream that can make it a bit faster overall.
@letterus @agx Possibly. GTK4's GPU rendering isn't well optimized for mobile platforms, but it already got pretty usable in GTK 4.2. There will still be some work needed in order to keep slow GPU-rendered clients from making the whole compositor slow (like https://github.com/swaywm/wlroots/issues/3026), so there's no single silver bullet, but we'll get there eventually ;)
@letterus @agx One more thing: a possible feature that could be added to phoc to make platforms like PinePhone faster even with software rendering is to render everything in smaller resolution and then upscale while displaying. This will of course make everything blurry or pixelated, but should make it very snappy even with underpowered hardware.
Nevertheless, the compositor has no contextual knowledge on what's being displayed. Every client would have to implement that by themselves.