It’s a good sign in some ways that you are having this trouble. It means you are experiencing heavier traffic which means your ministry is getting views.
I looked around some and noticed you are running an older version of WordPress which might be attracting hackers some. I’d recommend upgrading but I know right now you’re going to be confused some by the new Block Editor so before you upgrade do a good, complete backup including your database and then install the Classic Editor plugin and enable that. Now you can do the update!
https://www.ads-software.com/plugins/classic-editor/
I’d also like to see a cache plugin there… I like W3 Total Cache but others like this one… WP Fastest Cache! Either is fine.
Those two items will lift a bit of the processor burden over time and assist the visitor’s browser with caching which will reduce some of the immediate future traffic load back on the website.
The only thing I saw that really concerned me is the size of the calendar feeds… those have grown quite large due to the recurring events accumulating over the years. I went back to Feb of 2017 and found events that repeat once a month or more often. It’s okay to use that recurring event feature but from time to time you should pare those back.
I’d also consider adding those to my robots.txt file to keep the search engines out of there as those change quite often and are huge and there are six different versions (maybe seven).
You might still need to upgrade your service plan… I know that’s an added expense but if your church is reaching people then maybe that’s one of the reasons you have the website.
I’d also recommend you add the site to CloudFlare… The free tier will give you one of the best DNS services in the world and, if your host is fast enough, you’ll gain up to a 17% speed increase and reduce the load even further on your web server.
Do update the WordPress system, plugins, and themes as needed. Backup early and often. Let us know if you have further questions.
