How to navigate the impracticality of Sigalovada sutra?
The truth of the Buddha's teaching is timeless and doesn't get affected by modern norms or customs. Imagine if it's influenced by social norms, then there'll be a possible scenario in a distant future where human virtures and values becoming severely degenerated. It'll be common practice and acceptable social norm for humans to do all kinds of evil and little to none of virtuous conducts. If going by the standard of that future time, the Buddha's teaching will be perceived as completely irrelevant, or at least only deemed valuable to a very very small number of people. The Dhamma drum will have so many pegs that it won't be able to make audible sound. So for the OP question, you'd have a better chance of finding a friend or a soulmate with similar mentality or conducts if s/he also cultivates similar virtues. Finding fellow Buddhist practitioners would be best, but any other sincere followers of other world religions would also be fine since they pretty much share similar codes of conduct. If all else fail, then it's perfectly ok to walk the path alone like a proud Rhinoceros