Filter repeater based on Dropdown onChange

Perhaps this way.
Attention not tested, just some theoretical thoughts!

import wixData from'wix-data';

var query

$w.onReady(()=>{
   query = wixData.query("Projects2")         
  
   
   $w('#myDropDown').onChange(()=>{
      let dropdownValue = $w('#drpCategory').value
      
      if (dropdownValue === "1") {   //Select All         
         query.eq("projectsInclude",true)
         .eq("projectsInclude",true) 
         .include("categoryId")      
         .limit(30)
         .find()
         .then((result) => {
            let items = result.items
            console.log(items)	
            $w('#repeater2').data = items;
         });
      }
      else {   }
   });
   
   $w("#repeater2").onItemReady( ($item, itemData, index) => {          
      $item('#text36').text = itemData.projectName;         
      $item('#text38').text = itemData.projectDescription;        
      $item('#image5').src = itemData.image1;         
   });