I feel for you and here is my story.

I have had the same problem for 4 weeks. Starting has gotten progressivbely worse.

I cleaned all the ground wires, I too added injector cleaner, I just spent a lot of money at a local garage getting the car towed and tested. I ran the battery out trying to start it.

The local garage guys can't figure it out. Not the fuel pressure, compression, etc. The mechanicals check out fine.
No codes and it starts poorly when (crank crank crank)cold, and once started runs fine. Will start up fine if you shut it off and start it right up again. If cold will not start easily. Just like yours.

Beware of pumping the gas pedal. I did that to get it started and ended up fouling the plugs by flooding the engine by pushing down(fluttering) the pedal to get it started. Starting got progressively worse. Thus I had to have it towed(I know all this now.)

I have an appointment with the volvo dealer next week and they think that it is indeed the fuel system. It may be dripping(leaking) fuel into the (cylinder)?, and thus the engine is flooded and when you start the car more gas is put in and the car has to crank to get the gas out to the point where it will fire up. When the engine is hot, the car will start right up because the fuel does not have enough time to leak in and flood, and the hot engine vaporizes whatever fuel does come in? That fuel drip leak is the is the first thing to check the fellow said. I bet the dealer will swap out a few parts and see if it starts up.
I, two hours from a dealer, do not have that luxury.

I will let the dealer figure out the actual problem, and by a process of elimination that fuel leaking thing might be it.I am not sure what is leaking gas (into the cylinders?,but your problem is similar, perhaps that info will help you and keep you from wasting time and money. I know so little about cars it hurts($).
Good luck.

I am sure there are many others who will have good suggestions.