I have found the HP values for my game with CE using info here. My process was:
Use CE to find 4 Bytes, exact value 320, First Scan.
Get over 74k values, run around and get hit.
When hit, pause, search "Decreased Value", Next Scan options get like 100ish values.
Die/Heal up at shirne, search for 320 exact value next scan.
Repeat until I had 6 values:
143B79264
7FF48EE9A814
7FF4927C4148
7FF4927C4160
7FF49E7BDF28
7FF4AC445AB0
These all seem to now consistently change when my HP changes. Froze all 6.
FROM software has a tendency to save data by 3s as a basic anti-tampering method. I remember back in Bloodborne I changed HP/Stamina values 3 times in the save to change them successfully.
I'm fairly certain those values change, but maybe the ranges are the same? There seems to be one in the low memory area and 5 in the last, though other user here got only 3 values and supposedly it worked for him to so I dunno.
Anyway, will test a little bit more to see if I actually have god mode or it's just the game seeing maxed out values, but there is a relative way to find the values with CE for those who don't want to wait.
Sekiro does not have online of any shape and form, so you can use it to your hearts content.