Yeah, I’m going to do that 
. I want to stress that this is purely a personal preference, but I don’t believe that a laptop is ever the right form factor for a sim PC. Perhaps the biggest upgrade step you could take would be to have a dedicated machine just for simming, which would be a desktop PC that is upgradeable over time. You could continue to use your laptop as your everyday PC.
Beyond that, then yes - a bigger and better screen is a must. 32" as a minimum, but bigger is better. There are some great 40"+ gaming monitors available.
You have the Thrustmaster TCA kit, which is pretty good, but there are better throttle quadrants than the Saitek. I’m guessing you use the Saitek for GA and the TCA stuff for airliners? The problem is that there are very few affordable GA-specific quadrants. Maybe consider the Honeycomb Bravo, which with add-on levers can be usefully configured for most aircraft types, which would likely replace all your existing throttle kit. There are plenty of very good expensive throttle quadrants like the VirtualFly stuff, but you’re in a whole other price category there.
On pedals - if you’re willing to enter mid-price territory then the Thrustmaster Pendular Rudder pedals are amazing.
Depending on how far down the road towards a dedicated cockpit vs stuff-on-a-desk you want to go, you could look at starting to build some stuff. Right now you’re propping up the TCA kit on boxes. A physical structure made of wood would be better. But then you’re in simpit territory and at some point it has to become a separate thing rather than a desk-with-stuff. I see you posted in the cockpit pictures thread - lots of good ideas there for how to turn a desk setup into more of a simpit.