I haven't found combats to be quick in any edition of D&D/PF including 5E or PF2. Fast combats really depend on the players. My players tend to overthink everything. Sometimes I sit as the DM as they overthink the combat thinking "Why didn't you have your action planned before it reached your turn?" Slow player information processing slows the game down more than the rules. As a DM I will gloss over a rule or forget a round or two and not worry about it to keep the game flowing. Oh well, combat is combat, sometimes people forget things even in real life. So it fits it would happen in game. Just keep going and get the combat done.
PF2 combats take a while like past editions. And players are still often the slowest part. And the fact I tend to run combats in a coordinated fashion once the players set off a series of events in a given area that brings everyone running. I don't like to run encounters as single encounters unless it fits like a party taking on a dragon alone in a cave or wandering one encounter a day exploration encounters. My combats are usually big multi-room encounters with 10 to 15 varied challenge monsters taking individual actions on different initiatives closing in on the PCs from multiple areas in an encounter area. That is never going to run fast no matter the edition. It didn't run fast in 5E or 3E or PF1 or PF 2.
The main difference for me is on the back end, not in the game play. I knew the Pf1 rules very well. I could run combats very quickly. But on the back end it took me far more time to set up encounters in PF1 than it does in PF2 and 5E. Which lowers the overall time I spend on encounters as a DM. The actual in game combats run about the same amount of time and hopefully will improve as I commit more of the PF2 rules to memory. But the back end of PF2 has been substantially lower because I've been able to run monsters and NPCs as written in the Bestiary and monster books without modification. And buffing and spell strategy does not require as intense preparation as it did in PF1/3E. It's about as complex to build and run encounters as 5E from a DM perspective with better balanced monsters out of the book for players using feats, multiclassing, and magic items.
PF2 combats take a while like past editions. And players are still often the slowest part. And the fact I tend to run combats in a coordinated fashion once the players set off a series of events in a given area that brings everyone running. I don't like to run encounters as single encounters unless it fits like a party taking on a dragon alone in a cave or wandering one encounter a day exploration encounters. My combats are usually big multi-room encounters with 10 to 15 varied challenge monsters taking individual actions on different initiatives closing in on the PCs from multiple areas in an encounter area. That is never going to run fast no matter the edition. It didn't run fast in 5E or 3E or PF1 or PF 2.
The main difference for me is on the back end, not in the game play. I knew the Pf1 rules very well. I could run combats very quickly. But on the back end it took me far more time to set up encounters in PF1 than it does in PF2 and 5E. Which lowers the overall time I spend on encounters as a DM. The actual in game combats run about the same amount of time and hopefully will improve as I commit more of the PF2 rules to memory. But the back end of PF2 has been substantially lower because I've been able to run monsters and NPCs as written in the Bestiary and monster books without modification. And buffing and spell strategy does not require as intense preparation as it did in PF1/3E. It's about as complex to build and run encounters as 5E from a DM perspective with better balanced monsters out of the book for players using feats, multiclassing, and magic items.