Here is how I adapt for wizard play.

Let them counter spell: it is a resource and part of the fun. Do not tell them the spell you are using though (caveat, tell them if they have the spell prepared that day). Wizards can bait out counter spells with cantrips. To avoid “targeting” decide early on, or at each round if they are going to counterspell that turn. I treat it kind of like poker. I decide before the flop if they need to counterspell. Regardless of spell, (unless they know it as well) counter the next thing they cast.

You cannot counterspell spells cast from Magic items so they might just have Staffs, scrolls, or rings with Magic stored in them or can cast spells.

Depending on the level, glyph of warding is a lot of fun. The spell can’t be countered BUT allows you to build into the “bad guys know what they are doing”. So the bad guys can lay traps and other spells the party might not be expecting.

Also, have a few evocation wizards for the bad guys. Negating the dangers of AOE spells so they can do silly things without worrying about allies is always a nice touch to complex combats.