Not true.
There are only three continuity errors in JL2017:
Mera has a terrible English accent which she doesn’t have in Aquaman.
Arthur has misty white contacts in JL2017 when his eyes are normal in Aquaman.
Mera acts in Aquaman as if her and Arthur are meeting for the first time, which is wrong because they’ve met before.
However ZSJL has at least six continuity errors and has one massive narrative bomb sitting in it that hasn’t exploded yet and probably will be the biggest reason they will never make ZSJL canon. I’ll get to that at the end:
Mera has a terrible English accent which she doesn’t have in Aquaman.
Arthur has misty white contacts in JL2017 when his eyes are normal in Aquaman.
Mera acts in Aquaman as if her and Arthur are meeting for the first time, which is wrong because they’ve met before.
Mera speaks of her dead parents in ZSJL but they are alive in Aquaman
Aquaman states that only those with Atlantean Royal blood can breathe on the surface but ZSJL shows Steppenwolf interrogating a bog standard Atlantean guard on the surface and he’s clearly breathing air.
Vulko shows up with Arthur’s spear (and armor) and throws it at his feet telling him to pick up his mother’s spear, except Aquaman shows Arthur having the spear his entire life, using it all the time and BvS shows him with it too. Vulko having the spear is a continuity error.
Someone also here just mentioned a continuity error with Cyborg’s creation too.
Then the last and biggest problem. Not an error, yet. But something they won’t ever carry on with and it’s probably why ZSJL will never be canon:
The baby.
ZSJL shows scenes of Lois and a pregnancy test. Then later in the movie in the ‘I bought the bank’ scene she’s shown walking into the house with a baby carrier. Either there’s a baby in there or there’s one on the way.
They can’t just hand wave a baby away. If they make ZSJL canon, there will be a missing baby as they won’t give this new bright, hopeful Superman a wife and a kid straight out of the gate.
The last one above is the biggest reason ZSJL won’t be canon and why they are so steadfast not changing their stance that JL2017 is canon.
ZSJL is the better film. But it doesn’t fit with the rest without causing many problems. So they’re just continuing to say JL2017 is canon. It’s easier this way for all involved.