Sync text files (.txt) between iPhone and Mac; and edit (in-place), and search them on iPhone

I keep notes in text files (.txt) in a folder. I want to be able to edit and search these on my iPhone. I currently use VS Code to edit the text files on my Mac. Currently, I sync them via Dropbox. The Dropbox iOS app allows me to edit text files on my iPhone, but I can't search the text files' contents, unless I upgrade to a paid plan (minimum C$16 / month). I tried Google Drive, but it doesn't allow me to edit text files on iOS. But I can search them. So this is the opposite problem that I have with Dropbox. Is there another solution that I can use, which allows me to edit text files on my iPhone, synced from my Mac, and search their contents? I'm willing to pay up to $10 for a one-time iOS app, or up to $5 per month, for this ability.