Give all non members WP Users a level based on its role.

asign-level.sql

#give all non-member WP users level 1 with a specific start and end date set
#change the level (1) below and start (2024-01-01) and end (2024-12-31)  dates below  and um.meta_value ('%subscriber%') to per your needs

INSERT INTO wp_pmpro_memberships_users (user_id, membership_id, code_id, initial_payment, billing_amount, cycle_number, cycle_period, billing_limit,trial_amount,trial_limit, status, startdate, enddate) 
SELECT 
    u.ID,  			# ID from wp_users table
    1, 				  # id of the level to give users
	  0, 				    # code id to give users
	  0,            # initial payment to give users
	  0,            # recurring amount to give users
	  0,            # number of cycles to bill users for
	  'Year', 		# period for each cycle
	  0, 				# total number of billings to do
	  0, 				# trial amount to bill users
	  0, 				# number of trial periods to bill users for
    'active', 		# status to give users
    '2024-01-01', 	# start date in YYYY-MM-DD format
    '2024-12-31' 	# end date in YYYY-MM-DD format, use '' for auto-recurring/no end date
FROM wp_users u  
INNER JOIN wp_usermeta um 
    ON u.ID = um.user_id
    AND um.meta_key = 'wp_capabilities'
    AND um.meta_value LIKE '%subscriber%'
LEFT JOIN wp_pmpro_memberships_users mu 
    ON u.ID = mu.user_id 
    AND mu.status = 'active' 
WHERE mu.id IS NULL;