It depends on what you consider "trendy". Just because it is popular, doesn't mean it is "trendy". Stella is along the same lines as the name Hazel, Maude, Betty, Emma for me.....popular way back when, and coming back. To me, "trendy" is names that you would see all of the time but not in older SSA.....like all of the Aiden, Brayden, Hayden, Caden, Jayden, Brinley, Kinley, Henley, Tenley, Harper, Piper, Bentley, Brantley, Beckham, all of the McK names, etc.
On this board, most people distinguish between popular (rank), trendy (trending upward over the past few years), and modern (the Brinley/Brayden names you mentioned).
Stella is both popular and trendy, but not modern. After a long hiatus, it hopped back into the top 1,000 in 1998 and has rocketed up into the top 100 since. At 73, it is popular, at 900+ places in less than 15 years, it is trendy. But is a trendy revival, not a modern invention/variation/elaboration.