CI platforms make it super easy.
Cloudflare made a big effort to make all software run on x86 and aarch64, and it wasn't that hard at all. Most things today work out of the box.
Many things that don't work, were not very robust to begin with, and fixing them to work on both platforms only made the software better as a whole.
Cloudflare could move to ARM servers in a days' notice, and would already do that if Qualcomm hasn't closed the Centriq shop.
The only real advantage I see for Intel today is AVX512, which can't be beat for some workloads, SVE would be able to compete for some workloads, but not all. However most workloads don't use vector processing instructions anyway. Still, I hope ARM improves their SIMD architecture further.
As for the ALU performance difference, it is very easy to bridge. As evident by Apple's CPUs and Qualcomm Centriq simply having four ALU units gets you to about the same ALU performance as Intel.
Branch prediction, cache performance and the interconnect are still much better at Intel processors. However Intel already peaked branch prediction performance, so the difference can only get smaller with time.