Being able to hit the 1000W probably isn’t the key target here and doing 1000W+ on the trainer probably isn’t going to be prescribed by TR - as it requires relatively good technique to pull off on a trainer without risk of hurting yourself or breaking something…
I would say that for crits, recovering from hard efforts when you’re already working hard is probably the focus required. Something like Guard or Xalibu would be good places to start as they sit you within the threshold range, then continually push you above it - forcing your body to clear the stress while still working hard.
Workouts like Olancha could also be good if you are simply chasing repeatability of a harder effort. Again, the lower peaks but very small amount of recovery time between peaks still simulates the recovery effort required.
For practise hitting the actual high power required in the races, i’d suggest this is still best done out on the road. If you can practise your sprint and get your peak power well above 1000W (so that 1000W becomes relatively easy) and you have good ‘recovery while still working hard’, this should give you the desired outcome.
Note: Two hairpin type ‘Hotdog’ courses are nasty and they are simply going to hurt. Reducing your bodyweight (if possible) will help with them as you have less mass to accellerate from slow speed.