Congratulations of deciding to go car-lite! We are a family of 4 adults (2 older parents, 2 young adult college students), and we share one car between us. Over the years we've made choices to keep the car-lite lifestyle viable, such as choosing to live where we work, having the kids attend the local community college for their general education units (free bus pass), turning the kids into safe cyclists at a young age, having a trailer to carry groceries, etc., as well as buying a house close to our city's downtown (walk score of 82 "very walkable" and bike score of 93 "biker's paradise).
I used to have an e-bike. My main lock was a heavy Abus chain lock (not a cable lock) that 5 years ago cost around $100. I rarely went out by myself, so most of the time my bike was locked up with another bike, using my chain lock, a cable lock, and sometimes a u-lock. It's harder to steal two bikes locked together.
Everyone else in my family has multiple bikes. They don't use the fancy road and mountain bikes for errands -- they have commuter bikes but not "commuter" in the bike industry sense. Their "commuter" bikes are older MTBs (as in from the mid-to-late 90s) and hold very little value. They each have a lock, either a cable lock or u-lock, and they only use one lock. Also, this is a biking town, so there are many places they just take their bikes inside.
I would keep the bike you have, but if you really want to replace it, I would look for a good, solid, used bike over a cheap bike from a big box store.