I’ve never used lacquer type of paints I’m afraid so I’m not certain… I’m however surprised that you’ve had bad results with Future. I’ve used Future over many models and this has allowed me to use a mix of enamels and acrylics (and watercolors) without any problems. What problems have you had?
In any case, washes made with watercolors would definitely not damage anything… Check my post about weathering from washes to pastels.