Greenwich stuff, and walking from Greenwich to Deptford
From maritime Greenwich you can walk along the riverfront to North Greenwich and the O2. Well, nearly all along the riverfront. Lovely views of the river and the far side of Canary Wharf, you pass a big ship moored as some kind of artwork with somebody living on it, the path goes inland to weave through through some kind of shipyard, and past a golf course incongruously next to a wasteland. It's a really surprising walk, you get a feel for the pace of change in the area with lots of (paused) building work, then suddenly you're at the O2 and all hustle and bustle, and you can catch the tube home.
If it is open, Wilson's music hall in Shadwell is lots of fun. Bar and theatre in a restored music hall.
Going down to one of the 'beaches' by the Thames at low tide gives a whole new view of the river and the boat traffic - near Wapping and Rotherhithe.
Horniman museum is a nice day out, if open.
Walking around the Olympic Park in Stratford is fun - if you take swim gear you can swim in the Olympics pool - surreal the first time without the crowds.
Rotherhithe is a pretty area with the Mayflower Pub (where Mayflower set sail from), a film costume library (was open to public pre covid not sure now), and an interesting history as was previously Docks and the place names reflect that. Previously you could catch a ferry from the tip of the peninsula to Canary Wharf, not sure if it is running now, or you could walk along river either to Tower Bridge or Maritime Greenwich, both interesting walks.
If at the Geffrye museum, there are lots of Vietnamese restaurants along Kingsland Road, and some cafes in the railway arches. You can walk to Haggerston park which has a city farm and great cafe.
Victoria Park is lovely, and you can walk along the canal to Limehouse Dock. Near Limehouse Dock is a big yurt with a cafe inside. Nice walk from there either to Canary Wharf or Wapping along river.