Even some of the hard lines clear 'bad' can be not be totally wrong if you stupid and think:
"kill "adulterers", it means to kill adulterers"
Now killing is perhaps harsh, but as mentioned also, older times were harder times and penalties were often harsher....
Now as to kill adulterers... That is not what most understand (or use it) to mean, it is not just unmarried sex..
It is very specifically breaking of weddings vows, which perhaps are the highest vows one can make.
Honestly breaking of wedding vows, should be harshly punished...
Now if your vows to your significant other do not preclude other partners, then (arguably) it is not adultery (though perhaps it is also not a marriage, per the bible).
With the bible you have.
1) it has been re-written how many times, re-translated how many times.... Even presuming the original disciples wrote it down right, how many human errors have crept in when translated... transcribed.... (or straight up re-written to be 'more understandable').
2) Since most of the ones mentioned here are from Leviticus isn't all of Leviticus dealing with "Any Israelite or any alien living in Israel', nothing about not going to heaven if you do any of those, just bad luck if you are an Israelite or live in Israel. (see how wonderful translations can be)