Slowing down simulation rather than increasing delta time?

There are reason why I would prefer fixed time stepping (constant delta time) in my project. Probably the best reason is that I’m using animations for non-cosmetic game logic, like the swinging of a melee weapon, which uses traces from last position to current position to detect any hits. Another reason would be particle system based projectiles that spawn so rapidly that even slightly higher delta time will produce a kind of (undesired…) shotgun effect. Is there a kind of “switch” for this? Since it doesn’t only affect my own code, I can’t work around it by simply using a different value. In multiplayer it would have to be restricted to the server ofc.

still interested…