Sounds like what you’re after is lxqt-panel. Problem is, it’s not quite ready yet - things like positioning settings, taskbar and a few other plugins do not work, last I checked, but feel free to check it out.
Presently, the main issue is that Qt’s layer-shell-qt isn’t complete yet - without layer-shell support, certain key taskbar-y things wouldn’t work, such as listing and management of active windows, menu popups, reserving the screen space etc. But I suspect it’s inching pretty close to completion with the looming release of KDE 6.
In saying that, what’s your issue exactly with Waybar? I use it on Wayfire and it works fine, and the taskbar plugin does display icons for Qt based apps.