Yeah, sometimes it's not just one pop bumper... all three of the pop bumpers on Solar Ride you can hit directly from the flippers, which is madness. I can definitely see from an operator perspective where direct shots to bumpers became more undesirable, between damage to the skirts (guaranteed a game would be down for an hour if you needed to replace one!), and that there were more enticing ways developed to encourage players to take dangerous shots with "STDM" rebound potential using things like bash toys.

You might try much warmer water... and most water slide decals require like 30 seconds minimum to be able to release even under ideal conditions.

I do scale models, and I always use warm to hot (above ambient) water, in a small bowl sitting on a mug heater. I've found decals work much faster and better with that.

It's been 20 years since I dealt with laser decals of any form, so I have no idea what they're like now. My understanding is you still need to clearcoat them even if it's toner, just to keep things from disintegrating.

I don't really use any wetting agents... it's just a soak in warm to hot water to activate the decal, and I apply a decal solvent once the decal is applied and dried out with a cotton bud.