He's waiting for you the game doesnt run when you log out lol
There is at least 3 new Elder temples you could go to other than the one you have spawned.
dig a trench if you need it and clear the area a bit, hide behind the posts and trees shoot fire arrows the best and just have a ton of arrows the Elder is quite easy to do.
This is exactly how I did him but made a smaller tunnel with ramp, that deep is not necessary just go under the base. Take your time have plenty of food and be patient.
https://youtu.be/gKTH8ZP0Fas
Maybe ask friends to help in the Valheim discussion hub pretty sure some will be happy to help out. Depending on their country and time zones.