MINIFICPP-2530 Fix various issues and cleanup OPC processors #5921

Job	Run time
rocky	12m 39s
ubuntu-22.04-clang	14m 50s
Docker build for integration tests	32m 18s
macos-xcode	35m 38s
ubuntu-24.04	5m 36s
windows-2022	45m 41s
Docker integration tests	25m 35s
	2h 52m 17s

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