Is the lack of success in friendships and relationships, despite one's best efforts, a sign of Allah's displeasure, especially when observing that some who are less religiously committed enjoy excellent social relationships, bearing in mind that "when Allah loves a servant, He makes him beloved to people"?

It is advisable to fear Allah and focus on His pleasure and good character with people, not on seeking their pleasure. If a servant sincerely turns to Allah and draws near to Him through supererogatory acts of worship, Allah will love him and grant him acceptance on earth and in heaven. What you observe of a lack of acceptance may be due to a flaw in your actions, so you must correct your intention and your deeds. As for the acceptance of others despite their shortcomings, it may be due to worldly interests that will cease when their cause ceases, and not true love.