I have a wordpress site on digital ocean with following configuration
ubuntu 18 OS, php7.2-fpm, mariadb, wordpress
they are hosted on a 80$ droplet, A 4 core dedicated cpu droplet still my site goes DOWN, on checking ...
Guessing you're using the default Wordpress Droplet "out of the box"? If so, you likely need to do some tuning as I recall it is not configured to run production.
Really truly need more information about what plugins...