F11 will show all current application windows. left/right arrows will step through them. Enter will select.

This is a subset of Shortcut for toggling between different windows of same app? which you can invoke similarly from the Cmd ⌘ Tab ⇥ app switcher, except in that case you use the down arrow to switch you into this mode.

If you'd find Cmd ⌘ ↓ better all round, you can change that in System Prefs > Keyboard > Shortcuts > Mission Control - though you can't do the inverse & make both F11

If your habit is to always go right for Cmd ⌘ Tab ⇥ every time, then you can quickly do left, down to flip through windows in the existing app.
You call as to which you might prefer

F11 will show all current application windows. left/right arrows will step through them. Enter will select.

This is a subset of Shortcut for toggling between different windows of same app? which you can invoke similarly from the Cmd ⌘ Tab ⇥ app switcher, except in that case you use the down arrow to switch you into this mode.

If you'd find Cmd ⌘ ↓ better all round, you can change that in System Prefs > Keyboard > Shortcuts > Mission Control - though you can't do the inverse & make both F11

If your habit is to always go right for Cmd ⌘ Tab ⇥ every time, then you can quickly do left, down to flip through windows in the existing app.
You call as to which you might prefer.