Hi,

You can create a python file in the model, for inherits the pos config settings

class LocationInheritPos(models.Model):
    _inherit = 'pos.config'

    location = fields.Boolean(string='Display Warehouse Stock')
    location_id = fields.Many2one('stock.location', string='Stock Location')

SRC folder-JS file

odoo.define('module_name.filename', function(require){
    'use strict';

    # inititlize the variables
var ProductItem = require('point_of_sale.ProductItem');
var Registries = require('point_of_sale.Registries');
var models = require('point_of_sale.models');

# load the models into pos
models.load_models({
    model:  'stock.quant',
    fields: ['location_id', 'product_id','available_quantity'],
    domain: function(self){
        return [['location_id', '=', self.config.location_id[0]]];
    },
    loaded: function(self, stock_quant) {
            self.product_quantity = stock_quant;
        }

})
# extend the product screen
    const NewProductItem = ProductItem =>
            class extends ProductItem {
                get quantity() {
                    var qty = this.env.pos.product_quantity
                    for(var i=0; i < qty.length; i++)
                    {
// 
                        if(qty[i].product_id[0] == this.props.product.id){
                        return qty[i].available_quantity

                        }
// 
                    }
            }
        }
        ProductItem.template = 'ProductItem';

        Registries.Component.extend(ProductItem, NewProductItem);

        return ProductItem;

});        

IN XML file SRC folder

<template id="template" xml:space="preserve">

    <t t-name="ProductItem" t-inherit="point_of_sale.ProductItem" t-inherit-mode="extension" owl="1">

        <xpath expr="//div[hasclass('product-name')]" position="inside">

            <t t-if="quantity">

                <div>

                <t t-esc="quantity"/>

                    # you can add i class and text in the particular session

                </div>

            </t>

        </xpath>

    </t>

</template>

Regards