This happened to me couple years ago. Reading on here I had the impression some people were able to get to theirs quickly & easily. Mine looked like yours and I felt stuck too. You're right that cable bundle is so tight it doesn't want to move anywhere. At the same time that yellow connector (and maybe 1 or 2 more) is hooked on to a rail or mount and so you have to get them unclipped from that as well. A small flat screwdriver helped.So today I wanted to fix it. However, I simply couldn't get at it! Will I have to remove the lower part of the airbox? If yes, how is that done?
Anyway, there's still this thick and stiff cable bundle covering it. Can that be moved or removed?
I did end up removing the lower part of the air box. There are several hoses and connectors. There is very little room to get your fingers through the frame so patience and circlip pliers will help. I vaguely remember an angle-screwdriver might have helped get to one screw through the frame from the right-hand side as well.
There is a video on youtube 'The Workshop' - Removing Throttle Bodies - he skips the actual bit we're interested in but just have a look about the 1 minute mark, he does very briefly point out the bits and pieces that need undoing. Might give you a better idea what to expect.
Once you're at the cabling, I just unwrapped as much as was necessary to be able to strip back the wires and make my repairs. I used silicone tape to wrap the bundle back up because I read electrical tape adhesive causes a mess when it melts, and I don't know where to buy proper wiring loom stuff from. I already had the silicone tape in my toolbox. It's non conductive, it's heat resistant, it doesn't have any sticky adhesive, it's just like a roll of thin silicone material but the magic part is it sticks to itself. So it won't come undone when you overlap itself a little bit each turn.
It even plugged up a small hole in my mothers garden hose. It's marvellous stuff.
I soldered my wires at the time (played with a ratcheting crimp tool first and wasn't impressed) but I've since had occasional error codes after turning the ignition key so a proper connector would have been best after all. I never thought I'd need to go in there again but when I want to get that ignition barrel off to inspect/clean the contacts I think those permanent wires will be a problem. So my suggestion is to buy a proper high current waterproof connector and do the job once