There is a mod called WardIsLove which gives you auto close option. But the ward itself is a bit costy and you won’t be able to craft it until you enter the silver era. It has a lot of cool features like keeping the mobs outside, prevent raids, protect structures, etc. It can also be adjusted so the mobs inside deals more dmg (good for arena). It even plays music, but only one song :(

Automatic Door Mod
https://www.nexusmods.com/valheim/mods/288
Looks like auto open is broken but from the posts auto close still works. I have not used it in a couple updates though.