No, 4G phones are not compatible with 5G networks. In order to connect to a 5G network, you need a phone that supports 5G technology.
While 4G and 5G use different network technologies, some 5G networks may use existing 4G infrastructure to provide coverage in certain areas. However, in order to take advantage of the faster speeds and lower latency offered by 5G, you need a phone that is designed to work with 5G networks.
If you have a 4G phone and you want to use a 5G network, you will need to upgrade to a 5G-compatible phone. Most new smartphones released in the past year or two support 5G, so you have a wide range of options to choose from.