My guess is not much of a change. ESPN is pretty entrenched in the 6/8 TV windows and they broadcast all of the SEC games. We may skew a bit more toward 8 as there are three schools in ET compared to one in the present Big 12 setup.
That said, there may be fewer spots on an ESPN Network for SEC games given the number of teams, meaning some get pushed to ESPN+/SECN+ -- there is more flexibility for 7pm tip offs on streaming platforms. And OU definitely prefers 7pm, as all of the non conference ESPN+ games are at 7pm.
I did a sampling of a few weeks of this season and the SEC Network games are usually on the 6/8 schedule, although one week they are 5:30/7:30 (with the 5:30 games originating in the eastern time zone). Maybe some 7:30 games would help a little.