Best Vinyl Bach - Solo Cello Suites recording?

I hope you got the latter of his two recordings , 1992 I think, where he plays the famous strad from the Smithsonian

Yes.

Fully agree that authentic instrument (and vocal style) performances are preferable (assuming a good performance of course). 30-40% of my ~4,000 LPs are such, including (for example) the 45 volume/90 LP Harnoncourt/Leonhardt Cantata cycle. I am not particularly religious, but hearing Bach's Cantatas performed in the spirit he wrote them could almost make me so. Modern, operatic renditions are also a travesty to my ears.

IMO original instruments give Bach what is needed, less precision and more mystery .Even more called for in vocals.

I am religious, but was not when I first heard the Cantatas
and Passions, but being Christian has brought new depth , to me at least.
Masaaki Suzuki. whose operatic style series on BIS has been
widely lauded, says you don't have to be Christian to understand Bach, that's as may be, but it sure doesn't hurt.

As an atheist and someone who is devoutly anti religion, I can also appreciate music by superstitious 18th century musicians…it's easy.

I own Heinrich Schiff but on CD's by EMI. I have no idea
if this performance is available on LP's. This recording is
made in 1985 so it should be possible.

Nadric, I have the Schiff too , never saw it on vinyl.
Good performance, but EMI overdid the reverb IMO.