Sources familiar with the situation tell us the Chiefs tight end just bought a new home in Kansas City, with the sale closing Tuesday. We're told he snapped it up for just under $6 million ... and, yes, for that kinda dough in KC, he's getting a place that's way bigger and more secluded than his old house.

Our sources say this pad is in a gated community, and it's a straight-up mansion ... 6 bedrooms, 6 baths and over 16,000 square feet of living space!!!

It also screams luxury ... we're told there's a pool with a waterfall attached -- plus, a tennis and pickleball court, not to mention a mini golf course. Now, as far as why he upgraded ... our sources say there were a few things nagging him, including needing more privacy.

We're told at Travis's old house, it was simply far too accessible, and was starting to become a tourist attraction ... with people swinging by and staking out the place -- Travis was getting uncomfortable with the situation.

That actually proved to be an issue as recently as this past weekend ... when TayTay came to visit Trav in Kansas City, only to have paparazzi park outside waiting for any shots of the couple.

Bottom line, he wanted to be in a more secure spot -- and yes, our sources say him dating Taylor right now certainly factored into his decision.

And, we know what some Swifties might be thinking, but, no ... we're told he bought it with his own cash, and it's his alone.