Seeking Advice for Smart Home Setup Issues

Hi everyone, I’m new to the smart home scene and I’ve been trying to set up my devices. I’ve encountered a few issues that I’m hoping you can help with. First, my smart speaker keeps disconnecting from the Wi-Fi. I’ve tried resetting it, but it doesn’t seem to help. The purple light keeps flashing, and it says the device isn’t registered. I’ve checked the Alexa app, but nothing seems to work. I’m considering getting a new router, but I’m not sure if that will help. Does anyone have tips on how to fix this? Also, I have a smart light switch that worked perfectly before, but now I can’t change its off time. The app just says it failed to save. I’m using the latest version, so I’m not sure what’s going on. Any ideas? Lastly, I’m looking for a good video doorbell without a subscription that works well with my existing setup. Any recommendations? I’ve heard about some brands, but I’m not sure which one integrates best. I’d really appreciate any advice you can offer. Thanks in advance!