Can't interact with objects

[Some dude]

So I had someone else test to compare hpl.logs, and well, the logs are pretty much same (including the errors with bones in the player), yet he can interact with other objects just fine, so that to me suggests that while the game is running correctly, there is perhaps something wrong on the user and/or hardware level.

I don't know about that. If this was true wouldn't more games be affected? Not only SOMA?
And what about the fact that I not long ago played well past this point without this problem.
It happened after I chose a new game.

In this case, the first thing I'd get you to check is your keybindings. Within SOMA, these can be accessed in the Options menu, or if you would to limit how much interactivity you have with SOMA so to avoid no longer being within the refund period, you can also simply upload your user_keys.cfg file, which should be either in the same folder as your hpl.log file, or in the <Steam_user>_<id> folder which is also in the /Main/ folder.

My keybindings are very customized. Don't like the default setup at all.
Upload my keys here?
Don't sound to smart.
And I bought the game on GOG.

Have you also tried playing with an XBox Controller or a third-party controller to see if the results persist? My friend who tested for me pointed out that while you can interact with objects, the animations cancel out almost immediately, which could be due to a problem with either your mouse or keyboard, though I would suspect faulty hardware to apply to games and the system beyond SOMA as well.

Unfortunately I lost the PC-connector for my xbox360 controller.
I wish I could try that since what your friend describes looks like my problem.
I could try the default setup with my current mouse. And then with another one.

@Mudbill
Yes they do show up. It's just that the action get's canceled out.