alright, final assessment. i have used the DME again in 2 brews out of 3 using the same yeast.
i've used the briess DME in probably 8 or so brews total over the past year and a half now as well.
yeast for all 3: OYL006 (WLP007 equivalent sort of)
brew 1 - porter with a sulfate:chloride ratio strongly towards chloride
3lbs DME, 3lbs 2row, 3/4lb pale chocolate, 1/2lb chocolate, 3/4lb crystal 60
carbed with 75g dextrose
brew 2 - bitter
90% maris otter, the rest bits of crystal, amber, acid malt, carafaIII
carbed with 85g dextrose
brew 3 - dry stout
3lbs DME, 2lbs maris otter, 1lb roasted barley, 1/2lb flaked barley
carbed with 75g dextrose
brew 2 is just so obviously different from 1 and 3. head retention is okay, but head is minimal on 1 and 3. head on brew 2 is massive and lasts while only getting a tiny bit more dextrose than the others. brew 2's taste is just bright and in your face, very hoppy. the water profiles for brew 2 and 3 were similar, brew 1's was different. im just seeing the DME as a likely factor in not making the best brews.
Options for other brands of DME are almost twice the price, while i was always able to get LME that tasted good from my LHBS for a price just slightly higher than the briess DME.
https://www.homebrewersassociation.org/forum/index.php?topic=13520.0(probrewer forum link in this thread is dead since it moved or something, but another verification of this)
https://www.homebrewtalk.com/threads/ion-additions-from-briess-pilsner-dme.186443/this thread is someone's estimates through math, but that would add something like 300ppm of sodium to the brews i mentioned above where i used 3lbs of DME. my tap water is at ~8ppm.
i know lots of people use briess DME, but im done with it despite its cheap price and ease of storage/use.