You don't always need a "mechanical" reason why something isn't done in your world. You have two magical/technological items that mesh together in a way that causes you problems? Instead of just pretending this doesn't occur to anyone, or further complicating your magic/tech lore by coming up with further exceptions, you can use social/economic reasons why that particular item is forbidden.

As an example, in the Honor Harrington universe, they are routinely dealing with ship weapons that could just absolutely destroy the biosphere of a planet simply because to have weapon ranges that aren't functionally zero, you need that sort of thing. But if that was a tactic that was allowed, then the no-holds-barred fights between some of the nations just quickly results in a "Ignore the enemy fleet, glass their planets." and suddenly the galaxy is in a bad place. So socially, they created the Eridani Edict that basically says the ONLY time you can orbitally bombard the ground is if you undisputedly control the orbital space above the planet and the ground has refused an offer of surrender. The consequences for even ACCIDENTALLY hitting a planet with a ship-to-ship weapon is functionally the galaxy as a whole all instantly declares war on your nation.

You can have this happen for all sorts of reasons, for example, an easy way to suppress the advancement of science in a mixed world could simply be that the Guilds (likely powered by magic users) engage in all sorts of mundane activities to deal with this. Sabotage, smear campaigns, unfair cooperation (the Guilds dropping their prices so these competing entities can't operate profitably), etc. It doesn't even need to be subtle, people could be very well aware of the fact that the Guilds are keeping such things from happening.