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For technical matters regarding your hosting and server, I would address a hosting company. For the rest all the speed optimizations (caching, CDN,...) are ok so I wouldn't waste too much time on that anymore. You can maybe check this mobile site tester from Google, but it won't give you much new information. The pagespeedinsights-report do show a good page speed, so this will not be affecting your rankings.

Me too, can you upload or screenshot the actual file that you are using

Hello, I'd say not, in the same sense that having a NAP in the websites footer doesn't have any negative effects on a website SEO ranking, in this specific content its the opposite

If the website is fairly old you could also use Google Webmaster Tools: https://search.google.com/ to do this type of research.  Go to Performance > click +New tab and enter the page URL.  You should check if ppl are searching for singular or plural more. Now the importance of this is based on user intend, you should ask your self the following question: "Do you provide a LIST /MULTIPLE  or things / services or one single service?" Google may show your page higher in rankings if you use plural and you provide multiple services as it's more relevant. Once you start ranking for plural and users interaction is good (ppl stay on your site, they click action button etc) you will also rank for the singular. Depending on what you provide you should write the title according to this principle: If you only offer one single thing write singular, otherwise always use plural. Check out the competitors,  check out their title, do they use singular /  plural or both? How long is their title, how often they use singular how often they  the plural in title. Another trick: Let's say most searches go for "best service" as singular but you notice a lot of queries with "top","list" or other combinations. As a test you may want to use both plural ans singular in a single title combining this with other relevant searched keywords. For example I would use: Selling Best Services - Top Service List for the situation above and see what happens in a few weeks.