Yeah that. Well, cpufrequtils and big.little clusters don't mix well as you probably noticed.
cpufrequtils itself has been deprecated for well over a decade.
Since cpufrequtils was being inflicted on otherwise perfectly working, DT-controlled boards, we've disabled it by default.
Boards that are proven to require it can re-enable it directly on the board as you've already found out or in the Armbian board file via 'CPUFREQUTILS_ENABLE=true'
All that said, the real, kernel-supported alternative, cpupower, requires kernel-tools build which is currently not provided by Armbian (nor is usbipd, perf, nor any other kernel userspace tool, due to the complexities of release-dependent building of parts of kernel which is normally userspace-agnostic).
until