Will this Acer monitor optimize my build when working/gaming? Or is there a better choice under 400?

LitDad

Build: Microcenter PowerSpec G706 Gaming Desktop Computer AMD Ryzen 7 3700X 3.6GHz Processor; NVIDIA RTX 2070 Super 8GB GDDR6; 16GB DDR4-3200 RAM; 1TB SSD
Monitor: 

MONITOR: Acer Nitro XV272U Pbmiiprzx 27" WQHD 144Hz HDMI DP FreeSync HDR IPS LED Gaming Monitor

TSTonyV

An alternative option I'd recommend would be the Dell S2719DGF. 

To give a quick comparison, the Acer monitor you chose has an IPS panel, and the Dell I recommended has a TN panel. TN panels have very low response times which makes them good for competitive gaming environments. IPS panels are known for having better color accuracy, contrast ratio and viewing angles compared to TN panels, i.e. "better picture quality." Modern IPS panels are now pretty close to their TN counterparts in terms of response times, but they do typically still fall just a little bit behind.

I've used the S2719DGF and it was a good monitor, and I'm currently using an LG27GL850 which is an IPS monitor, and I think you'll be happy regardless of which one you choose. That Acer and Dell both advertise a 1ms response time and you shouldn't notice any difference between the two, but this particular Dell monitor is pretty good in terms of color accuracy for a TN panel. So between these two it's really a question of: do you want to spend the extra money on a monitor with slightly better color accuracy? I think you'd be happy either way.