T1-4: The Temple of Elemental Evil

It wouldn't be that hard to do - dropping T1-4: The Temple of Elemental Evil into the Pathfinder 2e world of Golarion. There is a vast array of villages or even small towns where the Adventure could be staged. Maybe in the hamlet of Stachys, or the village of Redleaf, may be in Rookhill where the Adventure could be expanded.

Any thoughts?

Does it have to be 2e, though? Or Golarion for that matter?

Obviously, any module can be mapped onto any setting with enough work, and commercial fantasy settings are generally interchangeable, they are designed to be. But would it be more fun or less?

Would it be a better experience than PF1e or 3.5 in FR?

I see no problem with running a published adventure in a different system if that is what you want to do. I'm currently running a D&D5e adventure in the Daggerheart system.

As always, use the system that supports the story/experience you are going for. And if that is giving PF2e some love, go for it :)

Is part of your enjoyment of T1-4 its grand setting of Furyondy vs the horde of evil from Iuz/Zuggtmoy and the history of the Battle of Emridy Meadows? If so, then finding the story equivalent in Golarion is a must. If you're liking one of the all-time favourite dungeoncrawls and want to see how it works in Pathfinder, better start converting those stats. Don't forget you can play PF2e in Greyhawk, no need to shift to Golarion unless you have an existing player campaign there and want to set them up for their next adventure.

Here are a few options:

1. Nex vs. Geb (The Eternal Magical Feud)
Golarion’s ultimate rivalry. Founded by two incredibly powerful, immortal archmages—the wizard Nex and the necromancer Geb—the two nations fought a devastating, centuries-long war. The conflict was so intense it fundamentally scarred the planet, leaving behind a scarred wasteland between them known as the Mana Wastes. Today, Nex is a metropolitan magocracy filled with constructs and wizards, while Geb is a horrifying, legalistic nation ruled by the undead. They share a bitter, deeply rooted hatred held in check only by a tense, fragile truce.

2. Taldor vs. Qadira (The Blood Feud of Empires)
Taldor (a decaying, highly traditional empire) and Qadira (the westernmost, wealthy merchant satrapy of the massive Kelesh Empire) have hated each other for thousands of years. Qadira previously invaded Taldor in a massive war that lasted for generations. Though they are currently under an official peace treaty, the border is highly militarized. The two nations constantly engage in bitter border skirmishes, political sabotage, and deep-seated espionage.

3. Cheliax vs. Andoran (The Ideological Clash)
Cheliax is a ruthlessly lawful empire openly run by devil-worshipping diabolists. Andoran was once a province of Cheliax but broke away in a massive democratic revolution. Andoran is now dedicated to personal freedom, democracy, and the total abolition of slavery. Cheliax views Andoran as chaotic, rebellious traitors that must be reconquered, while Andoran actively funds underground networks (like the Bellflower Network) to smuggle slaves out of Cheliax, keeping the two at a permanent boiling point.

4. Molthune vs. Nirmathas (The Endless Civil War)
Molthune is a highly disciplined, expansionist military dictatorship. Nirmathas is a chaotic, decentralized nation of rugged woodsmen and freedom fighters who broke away from Molthune's control. The two places have been locked in a grinding, low-intensity war of attrition for decades. Molthune is obsessed with conquering Nirmathas to "restore order," while Nirmathas violently despises Molthunian tyranny.