Is a person's pursuit of advancement in life and self-esteem, love of excellence at work, seeking to get close to and know people, and publishing permissible non-religious content on social media with the aim of gaining their admiration, considered a form of worldly showing-off (riya'), despite sincere worship of Allah Almighty?

Ostentation (riya') is performing acts of worship seeking people's praise. However, performing permissible acts or worldly deeds for the sake of people's praise is not considered blameworthy ostentation. If your good deeds are purely for Allah, then cast aside obsessive doubts and interact with people normally. Do not worry if you perform a worldly act to gain their praise or admiration, for you will not be sinful by doing so.