Is the feeling that acts of worship and good deeds are done out of love for this world, not for Allah, despite the presence of devoutness and intense love for Allah, considered a waswasah (insinuation/whisper from Satan)?

It is obligatory upon a servant to strive against their self to perform acts of worship purely for Allah, such that their intention is devoid of desiring anyone other than Allah, for Allah is the One Who is most free from needing partners.

Among the devil's insidious ways is that he confuses a servant's intention or makes them doubt the sincerity of their worship, which might lead to abandoning the act of worship. Therefore, one must purify their intention for Allah and not pay attention to whispers.

A true Muslim, after performing acts of worship, remains between the fear of non-acceptance and the hope of acceptance, in accordance with His, the Almighty's, saying: "Is one who is devoutly obedient during the hours of the night, prostrating and standing, fearing the Hereafter and hoping for the mercy of his Lord?" and "And those who give what they give while their hearts are trembling because they will be returning to their Lord."

Have a good opinion of your Lord, perform acts of worship correctly, and do not pay attention to the whispers of Satan.