A couple of realities:
Any Parrot /Bird that has been scared and is in a panic to escape will crash, at speed, into walls, doors, windows, mirrors, etc.... It is just a reality and the strength of the escape reflex!
Short of fully blocking off a window, there is no sure way of eliminating the reality of a scared Parrot /Bird flying into a window with any type of distraction on or in front of that Window. (Note: As stated above, even a blocked off window will not fully eliminate this from happening.
Based on the above, everything from here is offered as a way to 'limiting' only.
Please read the recommended Thread provided above. That will cover the vast majority of possible methods.
When you start from the position of attempting to satisfy two very different end goals, there has to be trade-offs.
We have tried many of the suggestion as part of the attached Thread. They all work to differing levels of success depending of the Parrot /Bird and the set-up of the room.
What we have settled on is the installation of 50 mm (2") blinds. They have a very wide price range and choice of colours. In the cold season, one can fully close them to limit heat loss at night. In the day time, one can set the blind at an angle to match the position of the Sun. This allows over 90% of that days Sunlight to enter the room and support your plants. Now, that takes care of the Plants, correct?
But, what can they do for the Parrot /Bird? With the blinds set for anytime of the year, they nearly always will be at a some angle, which defines very limited access and by doing so, will direct a Parrot /Bird in non-panic flight to turn away. When the Parrot /Bird is in a full panic flight and headed straight for the blinds set at a slight angle. The 50 mm (2") blind can provide up to 38 mm (1.5") of give and additional give depending whether the Parrot /Bird hits it in the upper or lower Window section. In ether case, that small give will greatly reduce the the impact on your Parrot /Bird.
Remember that no approach is fool proof and training you Parrot /Bird on the physical limits of your room remains necessary.