How do I create search for multiple fields in dataset?

You have always to show your actual code, i can’t see your code and all the changes you have done.

I tought you would be able to do the rest of CODE

import wixData from"wix-data";

$w.onReady(function(){   }

export function dropdown1_change(event) {myFilter()}

function myFilter() {
    wixData.query("Therapies")  
      
    .contains('therapy', $w('#dropdown1').value)    
    .or(wixData.query("therapies")
    .contains('therapyType2', $w('#dropdown1').value))    
    .or(wixData.query("therapies")
    .contains('therapyType3', $w('#dropdown1').value))
    .find()
    .then( (results) => {
        console.log(results)
        $w('#repeater1').data = results.items;
    });
} 

This will probably be the ERROR throwing code-line…

wixData.query("therapies") 

Your Database-Name is surely NOT → “therapies” (perhaps → “Therapies”) ?

I did check the code, for me it works, if everything is setted up.
I checked it for just one filter-setting. Also the REPEATER do running.

Now it’s on you, to get this CODE running.

Good luck & happy coding.