How do you keep your toddlers busy during lockdown?

I'm interested to know what other parents do to keep their toddlers busy at home.

We've two daughters (2 and 3.5 years old). They are stuck at home for the last four months. In our case, we've to monitor them continuously because they do get into frequent fights even though they miss each other when one is napping. Going out during the day is not an option due to the scorching summer (TX).

Here are some activities we do

  - We bought/buy a lot of toys, puzzles but they lose interest after a few days
  - Make slime
  - Painting/finger painting
  - Playdoh/kinetic sand
  - Bathtub time (we do this multiple times a day mostly after slime and painting)
  - Coloring
  - Playing with lego
  - Occasionally play with Sphero and robots around the house
  - Papercrafts
  - Self-play until the sisters get into a fight
  - TV time when necessary (we want to avoid screen time, so no iPad, or phone)
  - The kids love asking Google Home Hub questions like make whale sound, etc. Even though YouTube and playing video is disabled, I think I've to hide it because they ask Google to see pictures of random things they pick up during the day.

Our challenge is their short attention span, they lose interest quickly and have to wait a few days before reintroducing them, so I'm hoping to build a long list of activities to try.

Thanks!

Edit: formatting