WordPress admin login first time slow

wordpress admin login take 12 seconds, if I logout, login again, it can login super fast.

the admin function once login is fast without any problem.

front website performace is fast.

WordPress 5.3.2

WordPress directory size 43.29 MB

Uploads directory size 1.51 GB

Server architecture Linux 4.4.0-ui19255.033-uiabi1-infong-amd64 x86_64
Web server Apache
PHP version 7.3.12 (Supports 64bit values)
PHP SAPI cgi-fcgi
PHP max input variables 1000
PHP time limit 30
PHP memory limit 256M
Max input time -1
Upload max filesize 500M
PHP post max size 600M
cURL version 7.38.0 OpenSSL/1.0.1t
Is SUHOSIN installed? No
Is the Imagick library available? No
.htaccess rules Your .htaccess file contains only core WordPress features.