Try these
1.) Limit the Redis memory usage to 2500MB and so on (for your ram 256-378MB).
2.) You use Apache, so you are novice. Other people don´t use this old thing... Try OpenLiteSpeed webserver.
3.) I don´t know what type of webpages you have, but when have Wordpress, you can try another type of modern databases, like MySQL 8.0 or MariaDB 10.6.
4.) MySQL optimization how much MB ram you set? You have very small amount of ram...