If you already got the booster jab, I think it‘s not too risky to do family visits, unless you have a specific high-risk condition or a condition that makes the vaccinations ineffective (immune suppression). I guess you‘d still have a risk comparable to influenza after three vaccinations, it‘s a personal decision whether you want to take that moderate risk.
For the unvaccinated, there is no real evidence that Omicron is milder than Delta. Most participants included in the South African studies which say it‘s milder had previous infections of another Corona variant and thus had a certain immune protection.