Caddy! It has HTTPS built in and provides simple but powerful configuration with sane defaults.

Example Caddyfile for a static file server:

example.com {
	root * /var/www
	file_server
}

I used nginx in the past, but didn’t like it’s verbose config files.

Apache, the OG HTTP server. Fast, well documented, battle-tested, FOSS and community-led (unlike nginx which is corporate-led). People will tell you that nginx is “faster” but never point to actual benchmarks. Both are ok.

Apache httpd if php is involved. Otherwise, nginx.

Both are highly reliable and efficient.

I have recently started using Caddy and I love it! FOSS, automatic HTTPS, super easy to setup and works well as a reverse proxy. As your website will not be complex, the Caddyfile would be just a few lines.

lighttpd, just to be different

Nginx

Hosting personal websites on your own hardware is such a pain, and I would imaging doing it on a rpi would be even more of a pain than on x86 architecture. If at all an option I’d recommend hosting on something like github pages or better still on a VPS.