Find the slow plugin. Do not stack three cache plugins.
A query, an autoloaded option, or PHP with no opcache. Page cache for anonymous hits, object cache if MariaDB is the wait. The theme is not rewritten.
One layer, then stop
Query Monitor or the slow log names it. A backup plugin running on every hit, or a security suite scanning uploads. We disable the offender. We do not replace your builder.
NGINX or one page-cache plugin, not both fighting. Cart and admin bypassed. Redis or Memcached only if the object cache is the missing piece.
A 4 MB hero is not a server fault. Opcache off is. We turn opcache on. We do not recompress the media library as the job.
A 502 is support. A fat wp_options is the database page.
Core Web Vitals for a theme that ships 2 MB of CSS is a front-end job. We will say if the server is already fine and the score is the theme.
€55 an hour. The first hour is the measurement.
Minimum 1 hour. If the wait is a paid plugin we cannot patch, you get the name and we stop. A bigger VPS is recommended only if the box is actually full.
WordPress slow, and the host says the server is idle?
Tell us if it is WooCommerce. No admin password in the first message.