For those who get compensated for them, a national holiday is a nice gift. For Shuls they create a little blip, since they have to decide whether to go with the regular schedule, switch to a Sunday Schedule, or some other permutation.
The switch to Sunday schedule seems like a logical move, since most people are off and they like to celebrate with a little more sleep. Even in neighborhoods with many minyanim, people generally prefer praying with the home shul advantage, so accommodating them with a schedule change makes sense.
Following the lead of many Yeshivas, some Shuls prefer not to acknowledge national holidays and keep to their regular schedule.
All things considered, it’s probably slightly better halachically to go with earlier times, although in the winter, when some Shuls daven before sunrise to accommodate working people, the later times would be better.
If you’re a getting things done type of guy, you might prefer the earlier weekday times, so you can get a productivity jump on your day.
Many Shuls daven a little slower on Sundays so that might sway a preference one way or another.
If you Shul can fill all the minyanim, adding an extra later minyan might make sense.
In any case, it’s a good opportunity to perhaps get there a little before the start time, daven a little slower, and stay for the whole thing if that’s not your usual practice.