My guess is, aside from the haters online, the word of mouth from even people who don’t like it will be “you should still see it anyway.” It’s the finale, and they’re going balls out, which will be an enticing curiosity even to those who haven’t liked the last two. The war is really more to grab the attention of the general populace who enjoy SW but maybe haven’t necessarily seen every SW film, and haven’t really thought about the series much since they saw TLJ or TFA in theaters.
There’s basically zero chance it will touch TFA numbers but also anyone who thinks it could is crazy. That hype will never again be topped in this franchise.