You have to look at it from a personal risk and affordability point of view. Not anybody else’s.
If you would struggle if rates went to 6% or more, maybe lock in now as nobody can predict the future.
On the other hand if rates went to 6% or more and you could comfortably cover that, then you may wish to take a gamble and fix for a shorter term in the hope that rates come down, but in the knowledge you are still comfortable if rates go up.
Over the historical long term, 3.49% is still low.