How to transfer/reflect documents from sale.order to project.task model? I am unable to achieve the result with my code.

The documents should not get jumbled. If sale order S0001 contains 3 documents then the project task related to S0001 should reflect 3 documents and if sale order S0003 contains 0 documents then the project task related to S0003 should reflect 0.

Please find the xml & py code below:

# -*- coding: utf-8 -*-
from odoo import api, fields, models, _

from Odoo16_Community.odoo.odoo.exceptions import AccessError


class ProjectTask(models.Model):
    _inherit = 'project.task'
    _description = 'Display smart button for attachments'

    sale_line_id = fields.Many2one(
        'sale.order.line', 'Sales Order Item',
        copy=True, tracking=True, index='btree_not_null', recursive=True, store=True, readonly=True)
    sale_order_id = fields.Many2one('sale.order', 'Sales Order', store=True,
                                    help="Sales order to which the task is linked.")

    display_attachment_button = fields.Boolean(string='Display Attachments',
                                               compute='_compute_display_attachments_button')
    attachment_count = fields.Integer('Attachments Count', compute='_compute_attachment_count')
    attachments = fields.Char("Attachments Name", compute='_compute_attachment_name')
    attachment_ids = fields.One2many(
        'ir.attachment',
        'res_id',
        domain=[('res_model', '=', 'sale.order')],
        string='Attachments'
    )

    def _compute_attachment_name(self):
        for rec in self:
            attachments = self.env['ir.attachment'].search([('res_model', '=', 'sale.order'), ('res_id', '=', rec.id)])
            rec.attachments = attachments[0].name if rec.attachment_count 
    def _compute_attachment_count(self):
        for rec in self:
            attachments = self.env['ir.attachment'].search_count(
                [('res_model', '=', 'sale.order'), ('res_id', '=', rec.id)])
            rec.attachment_count = attachments

    @api.depends('sale_line_id')
    def _compute_display_attachments_button(self):
        if not self.sale_line_id:
            self.display_attachment_button = False
            return
        try:
            sale_line = self.env['sale.order.line'].search([('id', 'in', self.sale_line_id.ids)])
            for task in self:
                task.display_attachment_button = task.sale_line_id in sale_line
        except AccessError:
            self.display_attachment_button = False

    def action_show_attachments(self):
        return {
            'name': _('Attachments'),
            'view_mode': 'kanban,form',
            'res_model': 'ir.attachment',
            'type': 'ir.actions.act_window',
            'domain': [('res_model', '=', 'sale.order'), ('res_id', '=', self.id)]
        }

    def action_view_so(self):
        return {
            "type": "ir.actions.act_window",
            "res_model": "sale.order",
            "name": _("Sales Order"),
            "views": [[False, "tree"], [False, "kanban"], [False, "form"]],
            "context": {"create": False, "show_sale": True},
        }

Thank you in advance.