Could anyone help tell me where I'm going wrong?!

I’m setting up multiple filters to filter a gallery of images - all of which are kept in databases.
I have the following I want to filter by (any or all)

MembersName
Battlefield
Countrylocation
Category

and then a gallery - IGDataset.

I have the code as below - the clear button works on clearing all of the filters but when I select an option from the dropdown (these are tables) it just clears all of the images.

I’m pretty much a beginner at this so don’t know where my issue is (I’m not getting any red dots on the code indicating there is a problem).

import wixData from 'wix-data';

$w.onReady(() => {

    $w('#IGDataset').onReady(() => {

 var filter1 = wixData.filter()

        filter1.filterTree.$and[0] = {}

        filter1.filterTree.$and[1] = {}

        filter1.filterTree.$and[2] = {}

        filter1.filterTree.$and[3] = {}

        $w('#MembersName').onChange(() => {

 let MembersName = $w('#MembersName').value;

 if (MembersName === 'MembersName') {

                filter1.filterTree.$and[0] = {}

            } else {

                filter1.filterTree.$and[0] = {

 'MembersName': MembersName

                }

            }

        })

        $w('#Battlefield').onChange(() => {

 let Battlefield = $w('#Battlefield').value;

 if (Battlefield === 'Battlefield') {

                filter1.filterTree.$and[1] = {}

            } else {

                filter1.filterTree.$and[1] = {

 'Battlefield': Battlefield

                }

            }

        })

        $w('#Countrylocation').onChange(() => {

 let Countrylocation = $w('#Countrylocation').value;

 if (Countrylocation === 'Countrylocation') {

                filter1.filterTree.$and[2] = {}

            } else {

                filter1.filterTree.$and[2] = {

 'Countrylocation': Countrylocation

                }

            }

        })

        $w('#Category').onChange(() => {

 let Category = $w('#Category').value;

 if (Category === 'Category') {

                filter1.filterTree.$and[3] = {}

            } else {

                filter1.filterTree.$and[3] = {

 'Category': Category

                }

            }

        })

        $w('#Search').onClick(() => {

            filter();

        })

        $w('#Clear').onClick(() => {

            $w('#MembersName').value = ""

            $w('#Battlefield').value = ""

            $w('#Countrylocation').value = ''

            $w('#Category').value = ''

            filter1.filterTree.$and[0] = {}

            filter1.filterTree.$and[1] = {}

            filter1.filterTree.$and[2] = {}

            filter1.filterTree.$and[3] = {}

            $w('#IGDataset').setFilter();

        })

 function filter() {

            console.log(filter1.filterTree.$and)

            $w('#IGDataset').setFilter(filter1)

        }

    })

})

see here how to set filter and reset filter:
https://www.wix.com/corvid/reference/wix-dataset/dataset/setfilter