Like other people suggested here, use opnsense instead of pfsense, and wireguard instead of openvpn. What I did for my homelab was to get a used HP t620 thinclient and an Intel 350 card with 2x 1gbps ports. You say you have 10gbps, so you would need a card that can handle that, and maybe a beefier CPU. For my setup, this tiny 65€ machine is not even feeling it. Single digit cpu usage for 2 wireguard connections, a little over 1GB RAM usage for a handful of services. I think for you an n100 with 4gb of ram is more than enough, but going for 8gb will be better and it will not be much more expensive.
I use Wireguard, so when I am outside, connected to my VPN, I use the internal DNS (pihole) for accessing internal network services using their fqdn.