I too am older with a bad back, but chicken keeping can be relatively easy to do with much less work than many pets. I find it very enjoyable, with a little bit of help from the family for any heavy lifting.
Many breeds are very docile especially if hand raised, though most won't be affectionate like a cat or dog. I know my chickens love me because I feed them treats, but I'm okay with that. I enjoy their avarice little hearts running after me and the treat bucket. Mine are more of an egg hobby than pets. (I have a cat and dog for snuggles).
If you want very docile breeds, you can choose Favorelle or Silkie. If you want docile blue layer, Ameraucana tend to be quiet birds. I find my Cream Legbar are a bit flighty. There are numerous new blue breeds like True Blue that would probably fit the bill.
If you want quiet, I definitely would stay away from roosters. Some can be very sweet while others not so much. Many tend to be aggressive, and you don't need a rooster for hens to lay eggs.
I'd keep the flock smaller, 3 to 4 birds, depending on how many eggs you want, so you can keep coops smaller and overall feeding and cleaning easy. (As I write that I want you to know I have 24 adult birds now with 7 chicks freshly hatched...I should warn you that chickens are potatoe chips...you can't seem to get enough).
As long as you can move feed bags (or have a healthy grandchild or family member do so), and keep the coop cleaning easy, chickens are very easy care. They are more eye candy than hard work.
I find having a raised coop, meaning the coop floor at knee or mid-thigh level, really helps me clean the coops without straining my back. I also place my opened up feed bags as a liner for the floors so that all I have to do is pull the plastic feed bag and the shavings come out in a quick swoosh avoiding shoveling and scraping. I then re-lay opened up bags down and place new pine shavings on top. This really helps keep the coops clean. I toss the coop shavings into the run which keeps the runs refreshed.
A hanging feeder that is top filled is essential. You can pour feed from the top. There are some nice automatic feeders out, but I keep it simple with a refill and check once daily. I like a large 1.5 gallon dog bowl for water as you can top fill and kick it over to spray clean with the hose. Many of the waterers require bending down, unscrewing, filling and rescrewing. There are some top filler waterers out there, and I have one I constantly fight with. I find them finicky with gravity flow mechanisms that get gunked up easily.
I'll link a breed chart below that gives you ideas for personality types for chickens. My personal favorites over the years have been Silkies (slow, small, sweethearts except when they become brooding momma bears), Barred Rocks (friendly and inquisitive), Barnevelders (real sweet hearts), the Red Sexlink hybrids (good layers and generally calm birds), Buckeyes (good for laying and meat, generally calm). I personally hated my Buff Orpingtons as they were nasty, lazy and mean, but many love their Buff Orps. I likely just got a poor batch from a hatchery. I'd stay away from Leghorns (Brown and White) as they tend to be flighty as do the Games. Most hybrids (mixed breeds) tend to be quieter. I haven't met a hatchery Rhode Island (production Red) that I've liked. Produce well but are mean tempered.
edited to add: I agree that Wyandottes and Sussex also are good choices for calm decent layers.
Good luck with your new chicken endeavor <3
LofMc
https://robertsfarm.us/breed.php