try this way:
order_lines = self.env['sale.order.line'].search([])

for order_line in order_lines:

if order_line.x_studio_phase_name_1:

tasks = self.env['project.task'].search([

('project_id.sale_order_id', '=', order_line.order_id.id),

('name', '=', order_line.x_studio_phase_name_1)

])

if tasks:

task = tasks[0] # Assuming you want to consider only the first matching task

order_line.quantity = task.x_studio_area_1

we first search for all the sale.order.line records. For each order line, we check if the x_studio_phase_name_1 field has a value. If it does, we search for project.task records based on the conditions you provided, and if there's a matching task, we update the quantity field of the order line with the value of x_studio_area_1 from the task.

Hi 

Try this Code

order_lines = env['sale.order.line'].search([])
tasks = env['project.task'].search([])
for line in order_lines:
    for task in tasks:
        if line.x_studio_phase_name_1 == task.name:
            line.product_uom_qty = task.x_studio_area_1

Regards