Performance Issue when overview of many templates as a grid is displayed

[hagege]

Description

If I use many different templates (for example 30 templates) with a block theme such as Twenty Twenty-Four, it takes a very long time until the overview is displayed under Appearance > Editor > Templates as grid. I have just deactivated all plugins (23 plugins, including many lightweight plugins). As expected, the template overview is displayed a little faster as a grid. But that doesn't seem to be decisive. Performance is ok in list or table view.

Step-by-step reproduction instructions

Appearance > Editor > Templates

Screenshots, screen recording, code snippet

Environment info

WordPress 6.6.1, Chrome

wp-server

server_architecture: Linux 5.4.203-1-pve x86_64
httpd_software: Apache
php_version: 8.1.29 64bit
php_sapi: fpm-fcgi
max_input_variables: 1000
time_limit: 30
memory_limit: 256M
max_input_time: 60
upload_max_filesize: 32M
php_post_max_size: 32M
curl_version: 7.74.0 OpenSSL/1.1.1w
suhosin: false
imagick_availability: true
pretty_permalinks: true
htaccess_extra_rules: false
current: 2024-08-14T17:28:47+00:00
utc-time: Wednesday, 14-Aug-24 17:28:47 UTC
server-time: 2024-08-14T19:28:45+02:00

Please confirm that you have searched existing issues in the repo.

• Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

• Yes

[aaronrobertshaw]

This issue might be similar to #64219 which flags a performance issue with the patterns page. There's a possible fix up for that in #64606.

Perhaps the templates page may need a similar fix while work on other improvements such as #64504 continue?