Basically, you are talking about a company pension that is deducted at source by payroll.
That seems to be the distinction you are drawing between that and making your own payments (and reclaiming on a tax return).
But that is NOT what salary sacrifice means. It's a different type of scheme. It looks the same on the surface, but there is a different set up, different rules, more admin, and you save NI as well as tax, which you don't with a "normal" company pension.
I'm afraid, as I have been trying to tell you, you're talking about something totally different.
But - the good news is, if this change comes in, it won't affect you. Yay!