You should point out to them the examples of Protestant man-made traditions I mentioned. See what they say.

No doubt they will probably say that even though there is no
explicit mention of such things in the Bible, nevertheless, the ***principle ***is. From there you just say, “Okay, well, the Catholic ‘traditions’ you mention are also in the Bible–in principle.” Then go on to show them in the Bible how certain Catholic traditions are there in principle, even if not spelled out explicitly–that is, if that can be done.
Also point out that even the Reformers, like Luther and Calvin, were not against tradition. They just thought that tradition should be evaluated in light of the Bible. They quoted from the Church Fathers, too, just like Catholics. They retained quite a few things from the Catholic Church, such as sacraments and infant baptism.
Wedding rings are another good example, and it’s related to an institution that all Christians hold to be very sacred–marriage. They know that, and they understand that. Start with what they know, to show them what they don’t know. Show them that they are surrounded by tradition but just don’t realize it.