I've done this for a few years as well. I use a terminal+tmux for most work including quickly editing files here and there but for some reason when I get to "proper" focus-mode programming my brain just wants a separate "application" to look at. And usually the terminal is on my secondary monitor while the "editor" terminal is full-screen on the main monitor.
I used to gvim but realized that I was getting almost no benefit (and occasionally the differences between gvim and my terminal caused minor annoyances).
Two things I do that help in this regard:
I use a tweaked config for the "editor" instance of the terminal that has a slightly different background color from my main terminal. This keeps them separate in my mind.
I use dedicated shortcuts for focusing each application I use (browser, terminal, slack, etc) and the "editor" terminal has its own shortcut. (The --class flag that the post mentions kitty has would be pretty helpful in this regard. My terminal doesn't have that so my shortcuts are based on title, which works well enough most of the time.)
I used to gvim but realized that I was getting almost no benefit (and occasionally the differences between gvim and my terminal caused minor annoyances).
Two things I do that help in this regard:
I use a tweaked config for the "editor" instance of the terminal that has a slightly different background color from my main terminal. This keeps them separate in my mind.
I use dedicated shortcuts for focusing each application I use (browser, terminal, slack, etc) and the "editor" terminal has its own shortcut. (The --class flag that the post mentions kitty has would be pretty helpful in this regard. My terminal doesn't have that so my shortcuts are based on title, which works well enough most of the time.)