I do not know on what country data your conclusion about omicron is based on but it really did overwhelm health care system in countries with low vaccination rates.

You could not compare masks with contraception because if you keep having sex, yes, it will result in pregnancy but infections diseases are not like sex because they come in waves and if you can outlive the current wave, your risk drops near zero until next wave hits.

Another important difference is that you could not have lesser pregnancy but you definitely can have less serious symptoms when you are exposed to lesser amount of virus particles.