Jiri only got that 1st round because of scoring a takedown when he managed to stay on the top, but didn't do much damage and Pereira escaped eventually. Before that, he was getting punished with powerful leg kicks.
That was a 5 round fight, so I wouldn't be putting too much weight on the 1st round. Usually fighters would just use it to "feel" their opponents etc.
And I think Pereira lacked a bit of confidence back then. That was his 2nd fight in the Light Heavyweight, he won his debut against Blachowicz, but it was unconvincing split decision and, before that, he got KO'ed by Adesanya.
So if we are to make predictions based on the first fight, Prochazka's best bet is to try to take it to the ground, but that's just not his style. And outstriking Alex will be hell of a task, but not impossible.
Jiri is huge, he could try TD but has to be ready to receive the blow he'd get. It's not easy to do when Alex has also trained for it, it's his weakness he has to make himself not vulnerable to TDs.
https://www.instagram.com/p/C8sxuXKvaia/
The two have become enemies even in the spirit world actually lol I wonder who they will consult after the fight. This is a battle of whose spirit has more magic tricks. Alex isn't denying it too so both are crazy which I think we could expect the worse in the cage.