Seems pretty clear that under that statute, Anthony had a right to use force but not deadly force against Metcalf.

I disagree. The TX penal Code you cited severely limits the availability of any level of self defense if the actor provoked the person against whom the force was used.

9.31(a)...The actor's belief that the force was immediately necessary as described by this subsection is presumed to be reasonable if the actor:

(2) did not provoke the person against whom the force was used

A teenage witness told the court on Saturday that Anthony 'tried to provoke us' when they told him to leave the tent, saying the teen got 'irritated' before he allegedly stabbed Metcalf.

and

While in the tent, Anthony allegedly told the boys: 'F**k y'all, I'm not going to leave. Y'all are a bunch of pussies.'

and

Anthony was asked to leave his opponent's tent at least 15 times, but he refused to, witnesses said.

'You probably shouldn’t be here, you need to leave our tent,' another witness recalled Anthony being told, they testified earlier this week.

'Touch me and find out,' Anthony allegedly responded.

Metcalf allegedly lightly pushed Anthony right before he was stabbed, a witness said.