Edit Nov 19 2022 – A.H.’s answer worked for me, and is probably what you want. The solution I gave below works but is more complicated and takes 20 minutes; A.M.’s answer takes < 2 min to be up and running.

As of Oct 2022, you can build Caddy 2 without needing to know any golang.

Thanks to this answer: https://stackoverflow.com/a/71622285/514608. I give a bit more detail below, using a couple docs at caddyserver.org. I ran this on Amazon Linux 2 Kernel 5.10 AMI 2.0.20220912.1 x86_64 HVM gp2.

The steps I give use "xcaddy". The "go/bin/xcaddy build" command takes a long time, over 20 minutes for me. I did the plain-old-build, without xcaddy, a few days ago. Today, when I do it I am getting a security warning from go about bits not matching. As described in the docs, if you don’t use "xcaddy" the resulting caddy executable’s "version" subcommand doesn’t work. With xcaddy it does.

Steps

sudo yum install go -y

go install github.com/caddyserver/xcaddy/cmd/xcaddy@latest

go/bin/xcaddy build
./caddy version
sudo cp caddy /usr/bin
# /usr/bin is the path used in example systemd unit files from
# caddy server.org, so if you don't use this path, you'd edit those
caddy version

#  following: see https://caddyserver.com/docs/running

sudo groupadd --system caddy
sudo useradd --system 
    --gid caddy 
    --create-home 
    --home-dir /var/lib/caddy 
    --shell /usr/sbin/nologin 
    --comment "Caddy web server" 
    caddy
#  not shown but required: you create a file named  /etc/systemd/system/caddy.service
#  as per docs/running link above, use one of the two unit files
#  as a templat.  After which, if you are using a Caddyfile:

sudo mkdir /etc/caddy

#  And then create a Caddyfile in there at /etc/caddy/Caddyfile

sudo systemctl daemon-reload
sudo systemctl enable --now caddy
systemctl status -l caddy