google maps not working offline even though I downloaded maps

Firstly, make sure your Google Maps is up to date. :-)

After that, double check and make sure your "bounding box" is large enough to encompass the desired off-line area.

Here's an image for reference:
https://imgur.com/a/hYDv9ee

My first clue was the fact that your downloaded offline maps data size seemed rather small. For reference, my average size US city offline map on my Pixel 1 device clocks in at around 300MB.

The larger the area needed for offline use, the larger the data downloaded to your device. I believe the cap in terms off single offline map chunk is around 1.5GB.

Note added by barlop:

The Google Maps version I had which seemed to be an earlier version,
was limiting the size of map I could download, and with that earlier
Google Maps version I wasn't getting a box either, just an area to
zoom in and out of. The solution for me was to update it which can be
done from google play store and tapping update. Then I could draw a
box to a good size and offline maps worked.