are you feeding them anything in this mix?

Not yet as none but 2 have sprouted

What temp are you germinating them at?

How long ago did you plant the seeds? How deep did you plant them? Did you keep them moist without being saturated? What temps are they being kept at? I would not be giving them any added nutrients until they are at least an inch tall.

The peat moss with perlite is basically what most potting mixes are comprised of and should be fine for germinating peppers. Using Vermiculite probably isn't a good idea since it retains moisture. Peppers do best in moist but not wet soil.

Aprox 3 weeks.

yes

29C

Temps are good, you seem confident that the moisture level is correct and it has been three weeks? That is longer than I would give seeds to sprout. It could be bad seed stock as well. It is looking like you need to start over at this point. Go back a decent potting soil as that worked for you in the past. Also, try some different seed stock if possible, but I am guessing it is the growing conditions that are hurting you and the only thing that sounds like it could be off is the growing medium. Maybe drop a photo of your growing setup and maybe someone will see a problem we haven't considered.

How old r ur seeds?