Not trying to rip Petras, and that's not what this post is for... but I just watched some of his Swarm19 film, and just the first 5 highlights of it, his pocket allowed him A MINIMUM of 3.5 seconds to throw. He makes a great throw each time. It appears (in this video) he'd never really had to face any adversity or issues with his O-line, and the competition may have been decent in Cali, but it appears pretty weak in these highlights. Watching the rest, there were 2 or 3 more throws that were quality where he rolled out but even his technique was not that great, he had time on the only time he rolled out to set his feet and throw. His arm is certainly a weapon and he can air it out maybe even more so than Alex, but he's got all the time in the world there. That's not the current situation now and he's not been able to use any other of his attributes (his legs or pocket awareness) to avoid sacks, or get out of the pocket and extend plays. Also at one point in the highlight a defender literally beats his guy, runs into spencer and just sort of shoves him with two hands 50% without tackling him, then kind of just watches him throw it downfield.. doesn't even try to tackle him. Phil would eat that kid alive.

Overall after seeing Spencer play now, and watching this (small small sample size) he doesn't appear to be making leaps and bounds in his development or fundamentals because he looks very similar with a much worse o line on a different offense.
One last thing is they EXCLUSIVELY used spencer in a shotgun. not once did he line up under center... HMMM...
going back to Alex's his pocket collapses several times around 2.5-3 seconds, and he's able to make the read, throw a tight spiral with a quick release and even extend plays and make the throw on the run. I'm not a coach and never will be lol, but certainly seems like Alex's been through more adversity in his HS career and is used to having some pressure in his face where Petras hadn't. In a vacuum, I'd take Alex all day. But the different systems, different levels of comp, it's just fun and interesting to compare things.