See wp_schedule_single_event() function. The general idea would be each time after you are done with a batch of users schedule next run few minutes ahead and pass info (such as offset from which user to continue) in arguments.
On larger scale I’d consider looking into alternate more specialized solutions or simplifying your process. Mass emailing is not easy to get right and WP is not developed with such tasks in mind.
Related Posts:
- Is it safe to store a user setting you don’t want the user to ever modify as a user option?
- User Profile / Add Custom Fields
- WordPress User Profile Upload – If page is saved file reset
- How to show a gloabl message on a user profile page (in back end)?
- How to save multiple custom user profile fields using repeater JQuery
- Get a list of all available fields in the User Profile
- Extra profile field as select box?
- How to get users by a custom field / by user meta data?
- How do you add a custom option to user data?
- Custom user avatar in the WordPress users listing
- Show User Their Password
- Adding Properties to User Profile and Displaying in List
- How can I sort get_users() by any value (last_name, user defined fields and more)
- Extra filed under “About the user” user profile
- Add description text under input field for new profile fields
- get_user_meta Short Profile Section
- Saving custom profile fields
- BuddyPress – Hook to Update Custom Profile Fields [closed]
- Calling custom profile fields?
- Redirect users based on custom field
- Custom User Profile Fields
- Add More Fields to Users Pages (Admin Panel)
- Register rest field for specific user
- Buddypress Add unserialized Profile Fields in Members Loop [closed]
- How to add field above password section in profile page
- WP_User_Query pulling ACF to loop
- Custom Fields – Taller editing area
- Front-end editing with custom fields?
- Excluding Specific Fields from Profile Builder Registration Form
- Custom Profile Fields move from BBpress to BuddyPress
- Passing args to WP_User_Query am I using meta correctly?
- UPDATE on SELECT results. A SQL query to swap Author with Meta Box value
- Customizing user data
- Set post to unpublished after one week depending on condition
- Linking Custom Fields to Database Records
- Show user info in a hovercard [closed]
- Display Custom Field for a Specific Role, but not for Admin
- Customizing WP user profile with custom fields
- Can’t save custom field on registration page
- Iterate through users and display users meta info at front-page
- Show image if author meta (profile fields) exists outside loop
- ACF: How to get users with a ACF flexible content subfield with a specific value AND layout?
- What is correct way to change user’s email?
- check for duplicate user meta data before updating
- Custom Field Repeating When Using foreach
- Front end register with custom fields
- Front-End User Profile
- Get emails from users by custom field SQL
- How can I create a profile field group that the user can’t see?
- Best Way to get facebook share count and update using wp_schedule_event or any other method
- No result update a custom field using wp_schedule_event
- Save custom field types with this function…?
- Display the output from Custom User Fields from a WordPress user profile on a WordPress Custom Page
- Adding data to User profile
- Delete user meta but only if found in array
- How do I update user email from frontend input field?
- Custom user registration fields in user_register hook
- Link fields in User Admin list
- want to add video upload option for front end user
- update_user_meta(): invisible data storage
- Extend WP_User_Query or WP_User to return all custom fields?
- Register author, facebook connect, publish posts from front end
- Updating custom fields with external data
- Calling a custom profile field only it it exists
- Echo text if field under user_meta is empty with get_users()
- Semi-Private Comments + page comments -> is it possible?
- how to add radio field on user meta on function.php?
- Send checkout page custom field in order email
- file upload user profile
- i want to send email on custom post field (job_status == 2) but it is not working
- Dynamically update Custom Fields to display new dates
- Is there a way to determine which user changed a custom field (and when)?
- how to execute custom field for structured data?
- use custom field value as featured image
- Metabox/Custom fields are not saving input data
- adding autosave feature to custom fields
- meta_query to check all custom fields
- Custom meta POST request fired twice when updating a post in Gutenberg
- Is there a way to save different data when USER interacts with the same POST?
- add different custom fields value to post class if permalink or index
- add meta box considers the selected option as post parent
- Can you generate a featured image from two images from custom fields?
- Trying to get custom field data in a simple plugin
- Showing the post only when there is title, thumbnail and the content in Custom Fields
- author.php not showing content if Author has no Posts
- How to get all wp_posts in wordpress fetched from database
- Custom fields multiple commas separated values
- submitting form to admin-panel.php returns 500 error
- Custom field metabox not showing in back-end
- Retrive acf fields in publish_post action for wp_mail
- Display taxonomy loop using custom field data
- Update custom field on the fly
- Issue on Creating Checkbox Field On Custom Post type
- Custom field disappeared from screen options
- Post meta data not showing in frontend, until hitting ‘update’ button
- Adding more fields to the registration form
- checking liked user in wordpress rest api
- How to add code to custom field to every blog post via php?
- Show image depending on the number in the custom fields
- Saving custom form data