I'm still using a Note 20U since launch as my daily phone, and a Note 8 as a spare line and both have original batteries. Still use my 2012 Note 10 tablet occasionally, original battery still gives me over 5 hours screen time or lasts 3 weeks as an alarm clock. My Tab S2 is still going too and I bought that at launch in 2015.
When I worked at Verizon we switched our phone security system over to a system that integrated phone charging, we couldn't disable charging without disabling the security alarm so our phones were now powered 24/7. Every last device swelled up in under a year, didn't matter if it was a phone or a tablet, or which manufacturer made it. Lithium ion batteries only survive so many charges and letting them die or remain fully charged degrades them as does extreme cold or heat.
Samsung holds the majority of Android sales in the United States, so when there is a problem with a few of them, people on YouTube will act like it's a wide spread problem impacting millions.