Check with your bases armourer at the weapons terminal, they'll give you the gauntlet blueprint after a few tasks. Once you get it built with chromatic metal and sodium nitrate, stick it in an open exosuit tech slot and youre good to go. Watch those hazardous plants, they pack a punch without protection but the gauntlets make harvesting exotic plants like mordite root and fungal cluster pretty safe. Worth noting, those old guides talking about buying it at stations or the anomaly are wrong now, gotta do the armourer questline, no way around it.

Tip: might be worth stocking up on materials before starting the questline, saves you running around later when you need to craft it.