Not all countersignals are that costly. For example, casual wear is common among devs. This signals that our skill set is valuable enough that we don't need to comply with corporate dress codes. Sometimes someone from a poor background turns up in a suit - for example, we had a QA guy who did, having converted from some previous career via a short course. Sometimes new grads come to interview in one, having been poorly informed by their parents or whatever. Continuing to wear different dress to your colleagues just makes them uncomfortable and doesn't help you, even if your skill set is not yet that valuable.
The more general piece of advice here is that you should take advice from those who have just succeeded at what you want to do, not someone who did so a decade or more ago (parental career advice is usually well out of date. For example, my parents imagined that an academic career was still the easier option)