Page Speed

Speed depends upon many things like your server speed, items being loaded on the page, images, and third-party scripts. To increase page speed you can use any cache plugins

https://wordpress.org/plugins/wp-fastest-cache/

OR

https://wordpress.org/plugins/w3-total-cache/

And also optimize your images. 

https://wordpress.org/plugins/wp-smushit/

If you go for the paid plugins then we will suggest you use the below plugins

WP Rocket : https://wp-rocket.me/

Nitro Pack : https://wordpress.org/plugins/nitropack/

Databases optimizations 

The last thing, you may use Load balancing techniques on your server 

https://kemptechnologies.com/load-balancer/load-balancing-algorithms-techniques/

For database, you can use Memcache or radis on your server etc https://www.baeldung.com/memcached-vs-redis