Elpida was purchased by Micron after the financial crisis (they bought it out of bankdruptcy for a swan song in 2013). Much of the Micron DRAM you might buy is made at the former Elipida fab in Hiroshima.
With ram, you can verify pretty quick what you are getting.
I really wouldn't want to buy any NAND vendor until a bunch of years after they build a reputation. It's too scary to get a decent bargain SSD drive that actually oh secretly dies really early, doesn't actually have anywhere near the endurance it claims.
https://www.klevv.com/ken/main
And don't forget about https://www.nanya.com/en/
While I never had a problem with https://semiconductor.samsung.com/dram/module/ , I think they will be rare/more expensive now, or 'soonish'.
For chinese CXMT and YMTC there is https://www.biwintech.com/
We live in interesting times!
(Cackling madly...)