September - Positano or Ravello or Sorrento?

I think Sorrento meets your goals best. It is definitely the best transportation hub. If you go high up the reviews I have read the hotels have transportation to town. Not sure about the B&Bs.

Ravello is a 15-20 minute bus ride to get to Amalfi to catch ferries. It may even be longer as last I heard the road was still closed due to repairs after an accident. But the views are outstanding.

If Naples, Pompeii, etc. are also on your itinerary, then Sorrento makes more sense as a central hub. The marina is below a steep cliff from where the town is, but there is an elevator for €1.10.

Here's my trip report from my April trip. https://community.ricksteves.com/travel-forum/trip-reports/trip-report-2-weeks-of-day-trips-from-sorrento

The bus from Ravello down to Amalfi takes about 30 min

I agree that Sorrento would be the best choice for your needs.

Check booking.com
They list apartments as well as hotels

Based on responses to your previous posts about this question, I think you can safely say that Positano is off the list? September is still going to be high season on the coast so expect it to be very busy, and taxis are not inexpensive.

https://community.ricksteves.com/travel-forum/italy/positano-italy-33b0b03f-185b-4a18-9fe8-ea65ffed8e8f
https://community.ricksteves.com/travel-forum/italy/italy-june-2023-positano

I'll vote for Sorrento too for ease of accessing ferries and mostly flat terrain in town. "High up" can still be an issue there unless you're located in the main part of town and not up in the hills but there may be something along the edge overlooking the bay. If there is, I would expect it to be expensive.

Editing to add: Have you looked at the AirBNB website to see what is even available in September & descriptors/photos of the properties?

Another vote for Sorrento. Easy transport hub, giving you a lot of options for trips on the Amalfi Coast, Naples, Pompeii, and Capri.

Don't forget Rick Steves' suggested Mondo Tours . . . We're using them to see the Amalfi Coast out of Sorrento and to visit Pompeii and Herculaneum. https://mondoguide.it/

Except that Mondo Tours don't solve the issue of an accommodation to the OP's specifications.

Thank all of you - and yes will be in touch with MondiTours! Plus found a place high with views 3 BR in Praiano - not far from
Positano etc... you all have truly helped me! Thank you!!

Glad you found what you're looking for but you do know that there is no ferry service to/from Praiano, right? And that there are lots of steps there to deal with? The village is essentially vertical.

Your transportation will be limited to bus or taxi or private driver.
How will you get to Praiano- where are you coming form?
Where are you departing Italy from?

The Mondo Guide shared tours originate in Sorrento. You would have to get to Sorrento to take advantage of those.
www.sharedtours.com

The private tours are a bit expensive IMO-
https://mondoguide.it/city-tours-from-amalfi-coast/amalfi-coast-positano-amalfi-ravello

We recently returned from Italy and stayed in Sorrento for 5 days as our home base. The ferry service from there was very convenient. We didn't go to Positano because of construction of the dock which seemed to be an issue. So we wound up going to Amalfi via ferry. If you're looking to avoid steep climbs I would advise against Amalfi, and what I saw and heard about Positano I would say the same. I am a 63 YO make in good shape and my wife is 64, but doesn't exercise as much as I do so she didn't navigate the steep inclines as well as I did, but she did manage.

Do you need 3BR? Did you ask the owner about stairs outdoors and in? Do you need beach access?

67 yo woman reporting in here, in so-so shape but don't like stairs--I have a little phobia from a bad fall a few years back.

I stayed for a week in Sorrento and loved it. From there, took the train to both Herculaneum and Pompeii, got the bus down to Amalfi, then a bus up to Ravello (gorgeous views) and back, then a ferry to Positano, then a ferry back to Sorrento (which could be problematic if the ferry dock is still out of service). Also took a day trip to Capri. Just hung out in Sorrento for a couple of days. All of it was wonderful and it was a perfect location to reach all of those destinations. I didn't have a small garden, but I did have a balcony off my AirBnB with a view of the sea, especially lovely at sunset.