So, wanted to change the pads for the first time on a set of avid elixirs.

Try to push the pistons back, they don’t move much. Put the new pads in, super tight to the rotor (to the point where the wheel will barely go round). Tried with both avid and brake authority ones and the same happens. Eventually have to settle for the least worn pad on one side and a new one on the other.

Is this normal for avids? (never had such a nightmare with hope or hayes), am I missing something?

Are you pushing thepistons back squarely? If not, then they’ll jam and won’t retract fully, but if they’re moving freely but not going back all the way, you may have a touch too much fluid in the system, so loosen the bleed screw at the lever a touch, push the pistons back then re-tighten.

I had to bleed some from the rear last time I swapped pads. Same symptoms but I wedged the pistons apart and squeezed the lever to force out fluid from a sightly loosened bleed port. Easier to see how much was coming out that way.

Have you not got the red pad spacer that came with them.
Perfect for the job and resets the pistons for you. 😉
quick spray with silicon lube to free them up a bit..