Interesting spot.
Since you didn't give us info how many hands do you have on this opponent, I'll have to assume just that he is a regular player.
If you don't have any notes/reads this is my thought process here:
Your sizings on every street are made to get the whole stack in (according to eff stacks from pf) on the river if we don't get any raise.
That's excatly why your play should be adjusted according to board and range of opponent.
So in this case I would c/f river, because It is according to the plan,
you avoid getting stacked if it gets messy till the river and as you figured it gets
Now on the other hand, if you 3Bet preflop 4x instead of 3.5x the pot OTF would be 2.45. So you bet the whole pot. Why would you do that? Because I believe that there are Ax and Axs and possibly some FD hands that doesn't fold that flop. So OTT pot is around 7.5 and remaining eff stack is 6.5 if I am not wrong. So you get it in before river.
If he called you OTF w Axs or Ax or any FDs he won't fold OTT. So I think that's more +EV play in the long run also 'cause you avoid bad river cards for you.