I didn't need to teleport to get to the forge. It's not required.
But if someone did do it that way, I don't see a problem with it.
I enjoy the teleport feature in the game. It improves the quality of life. In addition, I like the way it's flavored as old Netherese magic.
As for the distance between places, I suspend disbelief and accept that the distances are condensed so we don't have characters running in this and that direction for five hours at a time just trying to get somewhere.
To each their own, of course.
The issue is not that there isn't a "fair" path to the forge (I've since seen videos of people doing it). The issue is that the most intuitive path to the forge is cheesing the fast travel point rather than using the "fair" method. Dungeon construction should encourage follower paths as discussed here:
I had the exact same experience as OP, and I really disliked it.
Important area should never be only available if all your characters have the good spells/features/items or through teleport runes.
A locked gate with a lever inside to open it would be better. This way you could explore with a character that has special abilities and that would open the path to the others rather than having to "exploit" the convenient runes.
the locked gate with the lever is just an example. But there should be some less cheesy game mechanic that enables party members to follow another member who has some sort of mobility skill (jump, misty step, etc...). That can be done through dungeon design (e.g., the locked gate) or ability/item design (e.g., teleport pyramids, "50 feet of rope").
