That is me!
It's funny, I was thinking about this recently listening to the Delta Flyers on the "Equinox" two-parter. Robbie was absolutely certain that they had produced both halves together at the end of season 5, because the big guest stars wouldn't have come back months later. He kept saying versions of "you can't trust that actors like this will still be available!"
And I'm listening to it and thinking, how does he not know you can book them for both episodes at the same time? I've cast guest leads in season finales and simultaneously made the deal for them to come back a few months later to shoot the next seasons premiere. (Though you do need to already have the pickup for next season to do this -- if you're just hoping for a renewal, you talk about it with the agent so they know you want their client back if all goes well, and then you hope like hell they don't get a better offer in the meantime)
But you can also do it out-of-sequence, if that helps you in some other way. I once did a show with a one-season series regular who did her entire seasons worth of shooting in a couple days. We did 3 days with her in the middle of the season and then brought her back for 2 more days at the end, and aside from her scenes we shot everything one episode at a time, the classic way.
Creative scheduling is MUCH more common these days than it was in Voyager's era, because TV has become such a different beast in recent years, and exploding production makes it all so competitive that now shows are forced to do this to get better talent. There's also series now that are so technically ambitious that you have to basically toss out an episodic shoot structure and block shoot according to locations or whatever in order to make it happen at all (Picard season 2 seemed to be doing a mini-version of this, looks like it was shot in 5 blocks of 2 episodes each)
But, generally speaking, the more you can keep the production of an episode within the days allotted for it, and the more you can do it one-at-a-time, the more smoothly things will run logistically, since that's the model TV was built on. The more you wander outside of it, the more union rules will start to trip you up. In the example of the series regular with the condensed schedule above, you have to offer the director of each episode the option of coming in to direct any material for it, so on those shooting days with her we had multiple directors running around, all of them directing different scenes. Bringing all these directors back increases expenses for production, but they were willing to incur it because it was the only way we could get this actress, who otherwise was too big for our show.
Berman Trek was such a machine, and productions had so much more leverage against the actors back then, I have to imagine instances of twisting the production schedule to accommodate guest actors were rare to nonexistent.
Let me know if that answers it fully.
