W/o a tensiometer, wheelbuilding becomes entirely a judgement call.
Hence reliant on experience, innate ability etc etc.
Some will get it right (enough) anyhow, some won’t.
In short, if your hands/ears aren’t calibrated, your tools need to be.

If nothing else, a tensiometer makes any discussions following a failure a lot more fruitful.

”I had DS tension up to 110 kg” is a better starting point than ”I think I’d gotten the DS tight enough”.

If you don’t want to buy the tool, maybe try a spoke tension app:https://www.google.se/search?source=...06.H1_VB5KrhW8