I have heard others say the same as you about Ubiquiti devices. I genuinely curious what bottlenecks you've hit.

I've only been using Ubiquiti as a pro-sumer, but it has held up well for my use case of Plex and little game servers.

I use a Synology NAS for my storage though, which is a slightly beefier mobile AMD chipset.

I'd be very interested to know what I should and shouldn't expect from my ARM based network stack though!

It says 8 Arm Neoverse N2 cores in the blog post. So not directly ARM Cortex, derived from ARM Cortex-X3 but same family as NVIDIA Grace, Google Axion and AWS Graviton4.

It's based on Neoverse N2 which in our other platforms (e.g., ENVR Core, UDM Beast, EF Core) has contributed to vast improvements in performance versus ARM Cortex.

This is how they make their money. They put out underpowered crap and constantly churn them so you have to pay them regularly. If something isn't profitable to maintain it just goes EoL.