Are boycotts really the best solution to stop this epidemic in gaming?

Yes, but not if you don’t convince others to join you.

How can we best prevent these gambling grey markets and the gaming to gambling addiction pipeline?

Educate people on the dangers. Show them why it’s gambling, because there’s a lot of apologetics out there to trick people into thinking it’s not. Point out the same slot-machine-tactics they use to get people hooked.

And then convince them to boycott. The CEOs that put this shit in games know how to read sales numbers, and if sales start dropping (or player counts), they’ll soon figure out that it’s because of their lootbox/gacha systems.

Lastly, give people alternatives. I usually point people to Deep Rock Galactic, but there may be others that are better suited to people’s tastes. “Just leave” isn’t really effective if they don’t know where to go.