The iPhone 13 is a great phone, and the performance difference between the 13 and 14 isn’t huge. I would go with the 1 TB iPhone 13.
I tend to fill up my phone easily but it’s not an issue for me since I have an android with a micro SD card (256 GB for now). However, if I had an iPhone and plan to use for years to come, I would get the extra storage.
Also, avoid any fast charging options on the phone as it heats up the battery.
Other than that, just enjoy using the phone. Lithium batteries usually come rated for 1000 charge cycles so they should be able to hold at least 80 percent of their capacity if charged daily after three years.
I had the same question as well. I understand that both can federate and share posts and comments. Still looking for a definitive answer to this question though.