How to reduce the load on the server?

Question

Apache HTTP Server

I apologize if some of the questions seem extremely stupid. Competent criticism and comments are categorically welcome.
I use timeweb hosting (not advertising). On the Internet, I have come across negativity towards them. However, I have to be content with their services for now. My plan limits server load to 50 cp. And while the site was made in php without the participation of the database and the administration system, this was enough, but for several days in a row the load has significantly gone beyond what is permitted and reaches a value of 250-280 cp. This is due to a site update and raises a few questions.
The site now has sys. administration of MODX Revo, approximately 148 pages and 80 to 150 unique visits. That is not very big. Its pages are observed by sys. collecting statistics from google and yandex (analytics and metrics, respectively). Also, for the convenience of the SEO specialist, the Google Tag Manager service was connected. And also part of the content only on the main page is loaded using AJAX and an online consulting plugin. In this regard, 1 QUESTION arises: how much, theoretically, the listed plugins can affect the server load?
In connection with the site update, we set up 301 redirects from all the old pages of the site to the new ones. There were about a hundred redirects in total. Information was received from an SEO specialist that after "gluing" the pages, the load should return to normal. From this 2 QUESTION: should we expect a serious drop in load after merging pages?
In response to a request to the hosting technical support, they suggested: "analyze the server logs" and sent a file containing them. The structure of data from hosting, logs is as follows:
...
Apr 4 23:56:44 fiona apache_access: titul-okna.ru 185.93.187.31 - - [04/Apr/2016:23:56:44 +0300] " GET /administrator/index.php?option=com_menus&view=menus HTTP/1.0" 200 7295 "-" "Opera/9.80 (Windows NT 5.1; U; ru) Presto/2.9.168 Version/11.
It is clear that the part Apr 4 23:56:44 fiona apache_access: titul-okna.ru 185.93.187.31 - speaks of the date, time, domain and ip.
[04/Apr/2016:23:56:44 +0300] "GET /administrator/index.php?option=com_menus&view=menus HTTP/1.0" - date, time, time zone, requested page.
200 7295 - the first number is the server's response, the second number 7295 is a mystery to me. Tell me if it's not difficult, what does it mean? Perhaps it is the answer to the third question.
"Opera/9.80 (Windows NT 5.1; U; ru) Presto/2.9.168 Version/11.50" - user's web education.
QUESTION 3: How can the source of high load be identified by analyzing such data?
Most recommendations from the net say that using data caching will help solve this problem.

<FilesMatch ".(jpg|png|svg|js|css|pdf|ttf)$">
  Header append Vary: Accept-Encoding
  Header set Cache-Control "max-age=604800"
</FilesMatch>

4 QUESTION: Is it worth using a similar design or is there a more efficient way?
Well, the main 5 QUESTION: How, in my case, to deal with the load? After the preceding questions, it may turn out to be rhetorical.
PS Of course, the most obvious way out of this situation is to change the tariff plan. But this doesn't actually solve the problem of high load. And I would like to understand it. Thank you.

Answer 1

150 unique hits per day is not that much of a load, even for MODx Revo.
Just in case, check if you have got any muck.