Burton directed over two dozen episodes across the Trek franchise. While Frakes is more prolific, ironically Burton directed my two favorite Riker episodes, "Second Chances" and "The Pegasus".
He directed and guest stared in the 100th episode of Voyager, “Timeless,” where Geordi had been promoted to captain of the USS Challenger 15 years in the future. 100 is an important milestone episode, so you know the show runners has confidence in him as a director to assign him that episode.
Trek actively gave opportunities to its actors in the TNG-VOY era to learn and try directing. The number of Main Cast actors who've got directing credits is pretty significant. The full list, along with the episodes they directed, is here: https://memory-alpha.fandom.com/wiki/Cast_members_who_directed
Of the TNG cast though, Jonathan Frakes, Levar Burton, Gates McFadden and Patrick Stewart all have at least one director's credit in the series. Michael Dorn would also later do some DS9 and ENT episodes.
Hearing his experiences on Voyager, you really have to feel sorry for the guy. The higher-ups really seemed to have an axe to grind with him. It's kind of startling how you go from TNG where even now the cast gets together like family, to DS9 where it was like "It was a good job and the people I worked with were wonderful and professional and we produced something that we can be proud of," to Voyager, where the cast largely describes it as a cesspool of passive-aggressive resentment and largely only mended fences years later.