Im very similar to you, love gardening but can’t do strenuous stuff or heavy lifting.
My views on gardening have changed radically after reading The Garden Jungle (or gardening to save the planet) by Dave Goulson.
Now I only garden and actively manage certain area that are within my abilities and that are important to me. (Beds close to house, sunny areas etc)
The rest can be left to nature (with an occasional bit of help), and nature does a better job of protecting wildlife than we ever can.
I now participate in No Mow May, and then mow once a month thereafter. By doing this I discovered wild British orchids on my lawn. I don’t try and eradicate weeds any more. At the moment I have dandelions on my lawn, which provide early food for the bees which are just emerging.
Another example. Come autumn, I now leave my the plants in my beds instead of cutting them back as usually recommended. The brown stems make places for insects to last the winter, and dead foliage provides the new growth protection in early spring. And I keep in mind that you can’t have the birds and bees and butterflies with out the other creepie crawlies in the garden.
So I truly believe it’s completely down to your mindset. It will only be as much work as you want to make it.
If you think you have unavoidable hard work like cutting down hedges, check the received wisdom. We used to have a gardener (but I don’t need one now) who said after July for hedges (because of nesting birds). I checked and now do the hedges in Feb, March. - before nesting birds, but less foliage so much easier.