For me speed increase is pretty significant. Testing with Ookla's Speedtest I get around 60-100 Mbps download with 4G and around 300 - 500 for 5G so sometimes it's faster that my Wi-Fi which usually is around 300 - 400.
Realistically though I do not feel this difference, 4G seems enough. Do not see significant difference in battery life as well. In the past I think 5G did eat more battery where I am so I stayed on 4G for a long time before trying 5G again.