Thank you @wackyblackie. Actually the first load is, which is very slow, but it can be caused by Wordpress all-startup-scripts, no?
I’ve read some related answers but I would like to ask you, why can it be faster for others, like for @DavidLinux?
That is definitely not what it means. It is a possibility, but not absolutely the reason.
Yes. This is the main downside of WordPress. You can help reduce the first load by creating a cron job in the control panel, but cron jobs don’t work that well here. (You can try setting one up to load your website every 1hr and 5mins though, it might work).
If your site does not receive a lot of traffic, DDoS may be to blame. However, note that every reload of your site counts as a hit, so if you are constantly refreshing your site you can easily hit it yourself. Wait for the suspension to be over, than try creating the cron job. Using Cloudflare also may be able to help.