2.7 head rebuild or new engine?

I have a 2.7 3rz on a 2002 standard cab. I rebuilt the frontend last year. And now I’m thinking onward to the power train and tranny . Clutch is getting loose on me, I’m thinking it’s got another 20k miles before replacement. But if I’m going to go through the trouble of doing think that I’m thinking of replacing the head of the engine too and pulling the engine to do the replacement. Embarrassingly, I haven’t ever flushed the coolant or deleted the egr valve…..so I’m assuming it’s inevitable the head will blow. Are the crank shaft and pistons pretty good for getting at least another 75k mi out of it? I do oil changes every 3k miles. Is it worth rebuilding or just swap another in there. Thanks

I’m never getting rid of the dang truck.