Will the effort to perform prayer continue with difficulty, or will it fade over time, making prayer firmly established and easy? And is there a way to remain steadfast in it?

You must offer sincere repentance and feel remorse for the shortcoming of neglecting prayer, and strive against yourself to perform all prayers at their appointed times, especially in congregation, in accordance with His (the Almighty's) saying: "And those who strive for Us – We will surely guide them to Our ways. And indeed, Allah is with the doers of good." What helps in this regard are: keeping the company of righteous people, being mindful of the seriousness of neglecting prayer, making abundant supplication and seeking refuge in Allah, and attending circles of knowledge and gatherings of remembrance. It is more prudent to make up for the missed prayers.