How can colleagues be persuaded to follow righteousness and abandon sins, especially given their perception of a religiously committed person as an extremist, and how can one invite to God in such an environment?

Shaving the beard and shaking hands with girls or kissing them on the cheek is wrong, for it is impermissible to shake hands with a non-mahram woman. The call to Islam should be made with wisdom, fair exhortation, and debating in the best manner, advising one to avoid bad companions unless there is a necessity.