I used Overleaf as a postdoc, but I no longer have an institutional Overleaf account and the free tier is WAY shittier than it was when I was a PhD student. Like, I got ONE compile in. Of a two-page document. And then it told me I was out of compile time and I had to upgrade. Ha. No, thanks.
I used an editor when I was a PhD student, but I absolutely cannot remember which one, and I also remember that whichever one I was using was a pain in the hole.
Of course, a regular text editor and compiling from the command line is always an option, but I like having a dedicated editor. 🤷