For those wondering how long it takes to sync,
2020-03-20T08:17:21Z UpdateTip: new best=0000000000000000000f813e7f23162e1a647cd07a4851f016170f30785259dc height=622126
...
2020-03-20T08:26:35Z UpdateTip: new best=000000000000000000068db6dedd26ae638bf34a7498982483c77b117c4d7769 height=622262
549sec for 136 block
4 seconds per block
622262*4/60/60/24 = 28.8 days, assuming full block + segwit.
That's vague information, can you tell us :
1. Which RPi4 do you use (1, 2 or 4 GB)
2. Do you know if there are any bottleneck (either from slow internet connection or slow storage)?