I mainly used Wikipedia and Twitter and verified any sources I could. Also, China has no official sales body that certifies music, so none of those sales on QQ, Netease, etc. are not counted here.
Results in spoilers below, organized by group.
1. Dynamite (2020)
USA - 3x Platinum (3M)
Japan - RIAJ Diamond Streaming (500M)
Japan – RIAJ Platinum Downloads (250k)
Australia – 2x Platinum (140k)
New Zealand - Platinum (30k)
Italy – 2x Platinum (140k)
Spain - Platinum (60k)
Poland – Platinum (20k)
France - Gold (100k)
Belgium - Platinum (40k)
Mexico - Gold (30k)
Britain – Gold (400k)
Greece – Gold (1M streams)
UK – Platinum (600k)
Portugal – Platinum (10k)
Germany – Gold (200k)
Denmark – Gold (45,000)
2. Boy With Luv (2019)
Australia - Platinum (70k)
Canada - GOLD (40k)
Colombia - GOLD (10k)
México - 2x Platinum + GOLD (150k)
UK - Silver (200,000)
US - Platinum (1M)
Italy – Gold (35k)
Japan - RIAJ Platinum streaming (100M)
BWL Japanese version – RIAJ Silver Streaming (30m)
Poland – 2x Diamond (500k)
3. Butter
Japan – Platinum Streaming (100m)
Japan – RIAJ Platinum Downloads (250k)
Spain - Gold (20k)
UK – Silver (200k)
Portugal – Gold (5k downloads + 1.25M streams)
New Zealand – Gold (15k)
US – 2x Platinum (2M)
Italy – Gold (35k)
France – SNEP Gold (100k)
4. My Universe
UK - Silver (200,000)
Italy – Gold (35k)
Canada – Platinum (80k)
Portugal – Gold (5k downloads + 1.25M streams)
Spain - Gold (30k)
Austria – Gold (15k)
5. DNA (2017)
Australia - GOLD (35k)
US - GOLD (500k)
UK – Silver (200k)
Japan - Gold Streaming (100M)
JP. Ver – Silver Streaming (30M)
6. IDOL (2018)
Australia - GOLD (35k)
UK – Silver (200k)
US - Platinum (1M)
Japan - Gold Streaming (50M)
7. FAKE LOVE (2018)
Australia - GOLD (35k)
UK – Silver (200k)
US - GOLD (500k)
Japan - Gold Streaming (50M)
8. Mic Drop (2017)
Australia - GOLD (35k)
UK – Silver (200k)
US - Platinum (1M)
Japan – Silver Streaming (30M)
9. Life Goes On
Japan - Platinum Streaming (100M)
US – Gold (500k)
10. Permission to Dance
Japan – Platinum Streaming (100M)
Japan – Gold Downloads (100k)
11. Blood Sweat & Tears
Japan – KR Ver. – Silver Streaming (30M), JP Ver. – Silver Streaming (30M)
UK – Silver (200k)
12. Make It Right
Japan – Silver Streaming (30M)
Australia – Gold (35k)
13. Black Swan
Japan - Silver Streaming (30M)
Mexico - Gold (30k)
14. Stay Gold/Film out/Lights
Japan - Platinum Streaming (100M)
15. Your Eyes Tell/Euphoria/Let Go/ON/Spring Day/Anpanman
Japan - Gold Streaming (50M)
16. Spring Day/Dope/I NEED U/Mikrokosmos/Answer: Love Myself/FIRE/Crystal Snow/Don’t Leave Me/Magic Shop/I’m Fine/Save Me/Friends/Not Today/Dionysus/Best of Me/Blue & Grey
Japan - Silver Streaming (30M)
17. Waste it on Me
Canada – Platinum (80k units)
HOW YOU LIKE THAT: Canada – Gold, UK – Silver, Japan – RIAJ Gold Streaming
Ice Cream: Canada – Gold, Norway – Gold, Japan – RIAJ Silver Streaming
DDU-DU DDU-DU: Poland – Gold, UK – Silver, US – Gold, Japan – RIAJ Gold Streaming
AS IF IT’S YOUR LAST: Japan – RIAJ Silver Streaming
BOOMBAYAH: Japan – RIAJ Silver Streaming (both KR & JP version)
KILL THIS LOVE: Poland – Gold, Portugal – Gold, UK – Silver, Japan – RIAJ Gold Streaming
LOVESICK GIRLS: Japan – RIAJ Gold Streaming
KAMU: Australia – Platinum, Italy – Gold, Poland – Platinum, Portugal – Gold, UK - Silver
SOUR CANDY: Canada – Gold, USA - Gold
ITZY (Wannabe, Not Shy – RIAJ Streaming Gold; Dalla Dalla, ICY – RIAJ Streaming Silver)
KARA Mr.: Japan – Million (digital singles), 3x Platinum (ringtones)
SNSD Gee: Japan – Million (digital singles), 2x Platinum (ringtones)
Fantastic Baby: Japan – RIAJ Silver Streaming, 2x Platinum (digital sales)
BANG BANG BANG – Japan RIAJ Silver Streaming, Gold (digital sales)
SEVENTEEN: Don’t Wanna Cry – RIAJ Silver Streaming
Gangnam Style: Australia – 10x Platinum (700k), Austria – 2x Platinum (60k), Belgium – 2x Platinum (60k), Canada – 4x Platinum, Denmark – Platinum, Finland – Gold, Germany – 5x Gold, Italy – 2x Platinum, New Zealand – 4x Platinum, Spain – Platinum, Sweden – 4x Platinum, Switzerland – 3x Platinum, US – 5x Platinum (5M), UK – 2x Platinum (1.3M)
If I missed any act, please let me know.