DIAGNOSIS Yeah, this one's common. It's a network strength problem at the doorbell's location. The 2.4 GHz band has longer range but is slower and more congested; the Doorbell 4 needs a strong, clean signal for smooth video.
FIX In the Ring app, go to Device Health > Network. Check the RSSI value. -55 or higher (like -40) is great. Below -60 is problematic. If it's low, your router is too far or there's too much interference. The fastest fix is to install a Wi-Fi extender, but it must be a quality one placed between your router and the doorbell, creating a new network for the doorbell to join.
IF THAT DIDN'T WORK If RSSI is good, your internet upload speed might be the bottleneck. The Doorbell 4 needs at least 2 Mbps upload at the router. Run a speed test on your phone right next to the doorbell. If upload is slow, contact your ISP or consider limiting other devices' bandwidth during peak times.
HEADS UP Don't force it onto the 5 GHz band even if your router supports it. The 5 GHz signal has trouble penetrating solid walls and doors, so while it's faster close-up, it often makes the doorbell connection worse.