Help!!!

Imo -Atk+Spd are pretty awful ivs and +Atk-Spd is perfect.

Her speed isn't all that good in the first place. Even with the +spd she's not doubling much. +Atk for sure.

With Bold Fighter and Fierce Breath, her specialty is charging specials faster. Having less spd will likely allow units to double her and charge her specials even faster.

Here's Micaiah's iv chart (which can be found on her unit profile when you search her name on this site, as well as every other unit in the game)

Her +spd iv is 31, this is pretty slowish in comparison to the current meta now. Even before, 31 was average for speed, now you typically want a fast unit to have speed that range in the 40s. Some units will reach close to or 50 now when max merged and buffed. Her attack is really high, she can nuke a lota horses and armors from my experience. So yea, go for that