Optimise iteration and lookups #13

Job	Run time
build / build (ubuntu-latest, esp32)	4m 48s
build / build (ubuntu-latest, esp32c3)	5m 38s
build / build (ubuntu-latest, esp32s2)	4m 41s
build / build (ubuntu-latest, esp8266)	1m 44s
build / build (ubuntu-latest, host)	1m 44s
build / build (ubuntu-latest, rp2040)	2m 12s
build / build (windows-latest, esp32)	10m 17s
build / build (windows-latest, esp32c3)	8m 54s
build / build (windows-latest, esp32s2)	8m 11s
build / build (windows-latest, esp8266)	3m 6s
build / build (windows-latest, host)	3m 19s
build / build (windows-latest, rp2040)	3m 55s
	58m 29s

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