API WIX USER TO WIX MEMBER

DATASET or DATABASE ? → DON’T MIX THEM UP !!!

In your code…

.
..
...
wixData.query("GymTraining")
.eq("_id", userid)
.find()
.then((results) => {
    if (results.items.length === 0) {
$w("#button1").show();
...
..
.

You are queriying a → DATABASE with the ID → “GymTraining” <—
There are no CODE-PARTS showing anything about a → DATASET !!!

Also you are not really using your e-mail, instead you are using the USER-ID , to get related results from your —> DATABASE.

Did you already run the CODE ?
Which RESULTS did you get?

Show a screenshot with opened Object.