To add to what Jamie's written above on some of the more general points from a solicitors perspective:
Very few legal professionals will use pseudonyms for social media accounts, we're all just humans with normal lives and friendship groups at the end of the day. However anything you place on social media is ultimately a public communication and could be seen by your employer or clients so my advice would personally be to not post anything that you would not want your clients or your employer to see and never use social media to complain about work.
I only use social media to post occasional holiday or travel photos and that seems to be common amongst most of my friends who are in legal and other professional careers. Those rare moanings about work when going through a tough time are best done offline in the company of trusted friends.
Interactions with the regulator are very rare, the vast, vast majority of barristers and solicitors will go through their entire career without any regulatory issues at all and compliance with the associated codes is either quite common sense based or quickly becomes second nature.
Relationship building whether with colleagues and clients is important in almost any professional career. Be helpful, friendly and nice to others and they will likely be helpful back. You never know when, where and from whom opportunities and work might arise to develop your career. This is essentially all part of the marketing and building of your practice. Some of the most pivotal moments that advanced my career came from the opportunities I was unexpectedly given by colleagues who I'd previously built strong and helpful working relationships with.