Hey there. A friend of mine is currently developing a WS2811-driven Mosfet Board to power this "stupid" 12V RGB or 24V (FCOB) RGB stripes. We had the same problem, that there is nothing on the market to buy easily. Also the boards will be strong enough to power a lot more than 5m (probably 10A-15A). Our plan looks like this:
All IOs will be screw terminals, so no hassle to find the right connector. Just stick it in, and go. GaN mosfets for efficient switching without getting too hot. PCBs still needs to be produced, and parts need to be sourced. We are in a very early phase. The plan is to 3D-print a case aswell.
Controlling these boards with WLED will be amazing and perfect for artistic LED implementations.
So if you want to get more updates on this project, just dm me.