does my turbo feel like it slips because my wheel is slightly out of true

It's possible for a wheel to have flats spots. It's not inconceivable that it might cause issues on the turbo.

Is it wheel revolutions, or pedal revolutions? You're also going to put through more power at certain points in the pedal stroke.

What turbo, what tyre, what sort of intervals are you doing?

Though, TBH, the very expensive wheel on trainer that the ex and i used to use, slipped during high power intervals whatever combo of tyre/air pressure/roller pressure you used.

Cleaning the roller and tyre helps for a while, but still slips.

Going to a wheel off trainer all but eliminates it, unless you have a Neo, that still slips under higher torque loads.

If it's on every crank revolution though, it's just a lack of grip. Clean everything up and tighten the roller.

Do you release the roller from the wheel when not using the trainer? You'll get quite a bad flatspot/deformation on the tyre if you leave it engaged which I imagine could cause slippage.

I had this when my tyre had developed a slight flat spot. But the wheel was also most likely slightly wonky knowing me as well.

I’ve replaced my wheel on turbo (Tacx flow), with the Zwift hub. It certainly did wheelspin even when freshly adjusted with the app.
I think flex on big gear efforts contributed to the wheel spin.