My completely uninformed guess is that this project was in the works for years, and it's not simple to postpone. For example, they would have mapped out where the moon was going to be, what its rotation would look like, how they were going to approach, etc.

Perhaps this is easy to re-calculate for another year, but when you're dealing with narrow tolerances for error, maybe there's a heavy bias to just stick to the plan? They probably were also hoping for a PR win, which obviously backfired in this case.

Russia is working a balancing act their messaging of the urgency of the war. Suffice to say, Russia has not gone into 100% total war footing (either economically, or in terms of human resources).

Continuing to have "normal stuff" like space missions provides a sense of normalcy (especially to the groups who haven't been subject to conscription yet), which is presumably useful for stability.

Sometimes rulers need desperately a win to show

Space race also is a test for making better weapons.