hey maybe this " what is a reverse proxy guide " may help https://www.namecheap.com/guru-guides/what-is-reverse-proxy-server/
but you can try to build NGINX with HTTP/3 support enabled:
% ./configure \
--prefix=$PWD \
--with-http_ssl_module \
--with-http_v2_module \
--with-http_v3_module \
--with-openssl=../quiche/deps/boringssl \
--with-quiche=../quiche
% make