Hi OP. We were at the Ritz Carlton Abama for a couple of weeks in August, lovely hotel. But I'm not sure the beach at Abama will be right for you, because as you say it's a looong way down to the beach via zig-zaggy steps. There's a funicular to the beach and a little train that goes down the hill to the top of the funicular, but they're only for hotel guests (wristbands or names are checked). You can't pay to use the funicular and while we were there it often wasn't in operation anyway. I've done the stairs and wouldn't attempt with a toddler or pushchair!
So, you'd have to park up somewhere at the top of the hill, because there's no parking further down, carry all your stuff down the hill, past the hotel grounds (while avoiding being run over by the land - train or hotel guests/staff driving golf buggy type things), then tackle the stairs down to the beach. I wouldn't fancy it.
There were locals on the beach, with picnics and sunshades etc but they were mostly dropped off by car with all their stuff at the bottom of the hill and they'd tackle getting the stuff down the steps in a relay style - which wasn't always straight forward because the turning circle at the bottom of the hill is meant for the little train, not cars, so there'd be beeping and shouting!
The beach is pretty and sheltered but really not very big - I wouldn't particularly make the effort if I wasn't at the hotel. Also, the waves and current were quite strong. There are bound to be nice beaches with easier access - I'm not really familiar with Tenerife generally.
Also, be careful driving and get the 100 per cent covered insurance even if it seems expensive - we wrote off a hire car! It's full of sheer drops, hair pin bends and peole who speed around blind bends in the middle of the road!
In my experience, if you're after beautiful beaches a few steps away from your hotel then Fuerteventura is the island for you.....soft, fine sand that's blown over from the Sahara desert.