Both work in WoW Forever. Pick Bartender4 if you play a shaman, because 4.18.4 turned on its totem bar for Forever. Otherwise pick whichever menu you prefer: Dominos is set up by dragging bars, Bartender4 through an options window. Both have Forever releases on Wago, and Masque can skin the buttons of either.

Bartender4 Dominos
Forever version 4.18.4, 3 November 11.5.1, 31 October
Forever changes Totem bar turned on for Forever Fixed a display error on transparent bars. Supports client 1.60.1
Set up by An options window (/bt) Dragging bars on screen (/dominos)
Good if You want exact numbers for position and size You'd like to set things up by eye

Before you install either

Forever's own Edit Mode can already move, resize and add action bars. If all you want is a second bar in a different place, try that first. Nothing to keep updated. See UI setup.

Only run one action bar add-on at a time. Two of them, or one plus a full UI like ElvUI, fight over the same buttons.

Skinning with Masque

Masque 12.1.7 has a Forever release. It changes how action buttons look, and both Bartender4 and Dominos support it. Skins are separate add-ons, and each has its own Forever status: check the skin's page before you install it. One of them, Masque: Dominos, had a Forever release when we checked.

Keybinds

Both have a keybind mode: hover a button and press a key. If binds disappear after you log out, see settings or keybinds not saving. For more on binding everything to keys, see keybinding add-ons.

For the rest of a UI built around your bars, see minimal UI in five add-ons and the UI add-ons list.