Unlocked the door but alarm goes off when open the door

Sounds like you'll be reading the security system troubleshooting in the factory repair manual which is probably a good read at best 10-15 pages or something It sounds like you're transponder is not turning the security system off your door unlocking is working both ways with buttons and with reaching but sometimes or most of the times or whatever the transponder system is not disabling the alarm portion or something along those lines when you reach for the door it unlocks but it doesn't disable in Toyota software you can turn off some of these features and also check some things there but sounds like you're going to need a service manual

 

I had similar behavior in my gen 1 after replacing a door lock actuator. Several eBay merchants had cheap versions of the actuator that were missing the switch inside that indicates you have unlocked the door on purpose. They would work for locking and unlocking the door (so if you bought the replacement because your old one didn't, and you only tested that, you would think "great! that's fixed"), but then the car would be surprised if you opened the door after unlocking it, and set the alarm off. (And you'd be unlikely to think that was because of the new actuator you had just put in because it seemed to work.)

But if there is no history of replacing a door actuator in the car, then this probably doesn't apply (other than maybe giving a useful idea how the system might work), and it will be a matter of troubleshooting using the manual, as Tombukt2 suggests.