Pls, read https://www.digitalocean.com/community/tutorials/http-1-1-vs-http-2-what-s-the-difference. Make sure your server accepts http 1.2 requests and even better eliminate anything less. You can also use Cloudflare for this, even the free subscription does this.
In most cases eliminating http 1.0 and 1.1 also cuts back on hack attempts.