You can check whether s2idle or suspend (s3) is used by kernel 5.4 & kernel 4.15 by
$ cat /sys/power/mem_sleep s2idle [deep]
where deep is s3
Switching one to another can be done by "echo deep | sudo tee /sys/power/mem_sleep" or "echo s2idle ...").
If switching to "deep" fixes your problem, you can make it permanent by adding "mem_sleep_default=deep" to your kernel parameters.
You can check whether s2idle or suspend (s3) is used by kernel 5.4 & kernel 4.15 by
$ cat /sys/power/ mem_sleep
s2idle [deep]
where deep is s3
Switching one to another can be done by "echo deep | sudo tee /sys/power/ mem_sleep" or "echo s2idle ...").
If switching to "deep" fixes your problem, you can make it permanent by adding "mem_sleep_ default= deep" to your kernel parameters.