Some enthusiastic work done there, very much needed by the looks of it.
what may have made the engine bay cleaning easier is something I noticed you mentioned “elbow grease”, but you probably meant the had work rubbing and scrubbing. Well now you can buy Elbow Grease off the supermarket shelf. I think it’s Poundland I seen it in and bought it to clean the engine bay of my Auris Hybrid last May. It only cost £1, and is very strong chemical, I wouldn’t use it in a confined space! I protected any electrical connections with silver kitchen foil, sprayed an area, gave a scrub with the wife’s toothbrush (well I want going to use mine, was I), then just sprayed water to clean it away, then used paper kitchen towel to wipe dry. The water sprayer I used was a discarded spray you would use around the house ie lower pressure finger trigger spray. Shifted all the oily dirt wasily, then I used a automotive product or leave a shine on plastics and hoses etc.