Thanks for the detail and for the super helpful actionable advice! I'll give that a try. How would you go about asking the team why they keep their video off? Should I ask during standup, in Slack?
If you want to make the suggestion of adding video to a meeting, think about what the benefits might be for your team and whether there may be more suitable occasions to do so (eg sprint planning or a meeting later in the day). If your coworkers understand more of the Why behind your request they will hopefully be more willing to give this a try. They may also have valid reasons for not wanting to use video too often (camera shy, limited bandwidth, messy workspace, meeting is too early/late in their day, etc).
Another idea that might have less resistance versus changing an existing meeting would be to try starting something new (and optional), like a Tech Talk series. We have occasional internal Tech Talks, where the goal is short technical presentations or discussions (about half an hour) over one of our lunch breaks. Sometimes there are visiting presenters from other offices or companies. These sessions are great if you want to learn more about job-relevant tech that someone is learning, using, or building.
If your goals include fostering more social interaction and connection with the team, you could also try suggesting a format that more directly achieves that. For example, we started a Share & Learn series where anything is on-topic except work. The concept is to facilitate directed discussion about a personal passion topic. We plan for an hour (usually at the end of the day, once a month) with up to 3 speakers and around 15 minutes per speaker plus questions (delivery format up to the speaker). This has resulted in some great talks/demos/discussions which helped us learn more about our coworkers (and beekeeping, craft beer, technical interviews, video game mods, DNS, knots, ballet, ...). We also open those up to everyone in the office and encourage everyone to participate (irrespective of their department/org).
Some companies or teams may not be open to these sort of ideas, but circling back to your original question about trying to evaluate company culture before you accept a job... you can ask about these aspects in interviews as well. What does your team do to keep up with new tech? What regular social or tech sessions does the team have? Is there a budget for team lunches or social activities and how often do these happen?