The changes you have made are allowing your CPU to run faster. No more power limit throttling at 7W. Did you make a change to the power profile in some Lenovo power management software or did you only make changes in ThrottleStop?
Your CPU is running much faster. It is quite capable of running beyond 15W. The problem is that your heatsink is holding you back. Long term it can handle maybe 17W. The 10210U has a 15W TDP rating so your heatsink is just a hair better than barely adequate.
Will replacing the thermal paste help? It might. Will it turn an under designed heatsink into a world beater? Probably not. Here is a picture of the heatsink in a Lenovo C930. This laptop also has a 15W CPU. Any significant sustained load and within a few seconds, thermal throttling begins.
There is just not much metal to be found in that heatsink. I have seen thicker layers of paint compared to the copper metal layer that is being used in this design. The heatsink in your laptop probably looks very similar. The best paste in the world cannot fix the real problem.
Most manufacturers are turning out similar products. Small, light and portable usually includes poor cooling and high temperatures. The ones that are not running hot are probably throttling themselves to death.
You can use ThrottleStop to set the long term turbo power limit to 15W. This will sacrifice some performance but it will help prevent constant thermal throttling. You can also reduce the turbo time limit. The Intel default is 28 seconds but no laptop has a heatsink that can keep the temps under control when a laptop is operating at a higher power limit for this length of time. Maybe drop the turbo time limit to something more realistic like 3 or 4 seconds. Play with the two power limits and the time limit and you might come up with a compromise that you are happy with.
Some laptop manufacturers hard code the power limits so you are stuck with whatever they give you. Keep that in mind when shopping. At least Lenovo has left these settings unlocked in your laptop so you have some control over things.