I don't see the scriptures that you listed as anti-God. Maybe we both interpret them differently. This is my take:
1) Phinehas who performed a double murder when a Jew married a Gentile is praised by Moses.
The issue here was not "marriage". Numbers 25:1 onwards mentions that Israelites committed sexual immorality with the Moabite women and were worshipping the immoral God Baal. Things that were clearly commanded to have abstained from. Bringing a Moabite woman when people were weeping near the tent and committing fornication was an act of blatant defiance of the law.
'Murder' is an unlawful killing of an individual. However, what the Israelite man did was against the laws of Israel and was dealt with as per the law and not by a random act of personal vengeance. It was an act of personal dedication to the divine worship, something that Israel was supposed to uphold and not defy.
This was not murder, it was an open act of defiance. In current times, an open act of defiance to the sovereignty of a nation will attract severe punishments, sometimes death.
2) Moses is shown as exalting one nation over others
No. It was not like choosing the UK over the US.
Jehovah did not choose an already established nation of Israel. Rather, Jehovah chose Abraham due to his faith and blessed him that his family would be special to Jehovah. Israel became a chosen nation due to Abraham's faith.
However, Israel was not chosen to perpetuity. In fact, disobedience led to severe punishments to Israel and later banishment from being the chosen nation.
It was like having a special relationship with someone. Having a best friend or a special friend does not mean that I am being partial or that I don't love others.
and even authorizing them to own Gentile people as their slaves "for ever"
Slavery in Israel as not like the tyrannical or ruthless slavery practiced during the middle ages. Slaves in Israel were protected under the law and had their own rights.
Yes, as you said, Israel could own Gentiles as their slaves. However, Leviticus 25:46 onwards also says that Israelites could own other poor Israelite as hired workers. Above that, Israelites could even become slaves of the Gentiles. (Lev. 25:47).
3) Woman is spoken as the property of men in 1 Corinthians 14:34-35:
It speaks about the subjection of a wife to her husband's authority not being a property for sensual satisfaction. The subjection was not akin to domination, because, Ephesians 5:28 says: husbands should love their wives as their own bodies. A man who loves his wife loves himself.
According to Jesus, Jewish laws that include laws about woman such as the above should remain until "heaven and earth pass".
According to Jesus, the law would remain 'until everything is accomplished' (Matt 5:17-18). The law was accomplished when Christ was executed on the cross/stake. (Col 2:14; Gal 6:24, 25) Hence we are no longer under the law.
People who claim to be God’s own would shudder at such anti-God verses found in the Bible
No. For believers, these passages show God's wrath against law-defying people. It bolsters their faith in the God of Justice. That's how things are. We can do very little about it.
A person may shudder at the savagery mentioned in the Bible but may be completely fine with the more than 100,000 abortions done every day.
In the end, it is all about how a person spins these passages around to advocate his point.