Your post is not correct. Canon 2261 of the old canon law allows the reception of sacraments of heretics if they are still uncondemned by church authority for any just cause. It even states, that you are allowed to receive the sacrements if they are otherwise non available.
There's a lot to unpack there and you know it.
Issues of validity for one.
Then there is the question of whether it is possible to get an alternative.
Then also what type of sacrament.
Plus finally there is a question of prudence. Many people are getting sacraments regularly from the SSPX. Is that truly a "just cause". Doubt it.