This is your fault. You treated your players like adults. You forgot that they are manchildren and that you're running the game for a fucking reason. You tried to collaborate and used the word "we".
To play GURPS, I told my players that I'd be running a one-shot. I didn't tell them the ruleset. I gave them their character sheets and we played with the traditional RPG loop; I told them the situation, they told me what they wanted to achieve and how, I interpreted this through the lens of the rules and told them what to roll then told them how the situation changed.
After the one-shot, I told them I was running a limited-game fantasy campaign. We went through 5 OSR scenarios using the GURPS rules, and again I never referred to the ruleset except when asked directly. At the end of the game the players asked me to run some more in the same vein. I refused, because I had given my word on when the campaign would end and had brought it to the proper climax.
Next we started a Dark Heresy campaign, again rolling 3D6s. This was interrupted by Covid, but not before we had exploding skulls, a hulking gladiator getting knifed by the psyker and a skill-squad getting outmaneuvered and shredded by the party idiot.
You never reveal your dreams and long-term plans; feed your players what you want them to enjoy piece by tiny piece until they realise that they've eaten a ten-course banquet. A dndrone doesn't stay a dndrone long once they've discovered the joys of their choices mattering, of semi-realistic damage systems and of knowing what the fuck's going on with minimal learning regardless of game genre.