You can use pretty much any wheel-on trainer with your existing bike. Direct-drive should also not be an issue provided you put the right spacers in for your cassette.
I much prefer a stationary smart bike to any trainer, but they're very expensive. Cheap non-smart bikes have notoriously inaccurate power curves. If all you want is a workout and you don't care about simulation accuracy or accurate training load metrics, then any stationary bike is typically less fussy to hop on and ride, easier to adjust, cleaner, and quieter.