Best system for Nikon wireless flash shooting

What is the best solution to use 2-5 off-camera flashes (SB-800, SB-5000) wirelessly with the D850 body?

It must work at least to 30 m in distance, and each flash output level (Manual mode, 1/1 - 1/128) should be adjustable remotely at the body side.

Ideally looking for a portable, travel friendly solution.

It must work at least to 30 m in distance,

In that case, only a radio (RF) remote system will work reliably, and AFAIK no Nikon-made remote will fire both the radio SB-5000 and the optically triggered SB-800. So you need to look at 3rd party systems from the likes of Yongnuo, Godox, etc. that attach a separate trigger Receiver to each flash head.

Godox make a neat and cheap RF trigger system that allows remote setting of flash output. Unfortunately it only works with their own speedlights or studio strobes. However, replacing all your speedlights may well work out cheaper than a CLS/iTTL-compatible set of triggers.

You'll have to research the options for other 3rd party systems. None of them seemed particularly cheap to buy last time I looked.

I use the Yongnou 560 TX Pro system with 4 YN560 iii for church interiors. Each flash can be adjusted in power and coverage angle from the camara position.

Transmitter about £65, flashes about £70 each.

I personally manually adjust them. Auto everything doesn't help me.