HTTPS load balancer - use server

Hi all. My question is, if instead of the current config with two backends, if I can use 1 backend and on the frontend or something use the “use-server” to make the config with only 1 backend?

global
    log /dev/log local0
    log /dev/log local1 notice
    user haproxy
    group haproxy
    daemon

defaults
    log global
    option httplog         # Use HTTP log format
    option dontlognull     # Don't log null connections
    timeout connect 5s     # Default connection timeout
    timeout client 30s     # Default client timeout
    timeout server 30s     # Default server timeout

### Sendmail Configuration
mailers smtp_domain
    mailer smtp1 mailproxy.domain.com:25
    mailer smtp2 mailproxy.domain.com:25

#############################
### HTTP
#############################
frontend http_frontend
    bind *:80
    mode tcp
    redirect scheme https code 301 if !{ ssl_fc }

#############################
### HTTPS
#############################
frontend https_frontend
    bind *:443
    mode tcp
    option tcplog

    ## Only PRIMARY
    acl proxyonly_sni req.ssl_sni -i gitlab.domain.com registry.domain.com
    use_backend https_Primary if proxyonly_sni
    ## CLOUD - PRIMARY
    default_backend https

### Backend for Cloud
backend https
    email-alert mailers smtp_domain
    email-alert level debug
    email-alert from alarm@domain.com
    email-alert to alarm@domain.com

    mode tcp
    option ssl-hello-chk
    server Cloud cloud.domain.com:443 check fall 5
    server Primary primary.domain.com:443 check backup

### Backend for Primary
backend https_Primary
    email-alert mailers smtp_domain
    email-alert level debug
    email-alert from alarm@domain.com
    email-alert to alarm@domain.com

    mode tcp
    option ssl-hello-chk
    server Primary primary.domain.com:443 check