Are the Dhuhr and Asr prayers considered valid when performed in the office in non-straight rows, or in twos and threes due to the confined space and the mosque not being nearby?

The majority of scholars view straightening the rows as a Sunnah (recommended practice) and not obligatory. Therefore, one should strive to straighten the rows and stand shoulder-to-shoulder as much as possible. There is no sin if the rows are interrupted due to lack of space, and the prayer remains valid.