1: Yes, I think OGS volatility of higher ranks does not appeal to stronger players.
2: I can understand that you prefer using your Fox/Tygem 5d rank to attract more students, but I don’t think Fox/Tygem dan ranks should be used as a benchmark for the Western go world, because they don’t align well with other systems of the Western world. To me, using those ranks feels a bit like false advertisement.
When looking at the table at the end of https://idex.github.io/go-rank-survey/go-survey-results,
your 5d Fox/Tygem roughly corresponds to 3.5d AGA, 3d OGS, 2.5d KGS, 2d EGF. So it would seem proper to me if your OGS rank were about 3d.
If you’re OGS rank is consistently 1k-1d, something appears to be off.
Perhaps you don’t play a lot of ranked games against mid dan opponents on OGS, making the rating calculation inaccurate by of lack of data. Or maybe it is caused by the high volatility of OGS ratings (so it may just be a transient fluctuation). But it may also be due to other OGS rating system quirks.