Is people's love for a person an indication of the servant's righteousness and God's acceptance of him, and their hatred of him an indication of the opposite, even if the beloved one does not perform prayers, or the hated one prays and fasts?

You attain the love of Allah and acceptance among people on Earth through piety (taqwa), as Allah Almighty said: ﴿Yes, whoever fulfills his commitment and fears Allah - then indeed, Allah loves those who fear Him.﴾ And the Prophet, peace and blessings be upon him, said: "When Allah loves a servant, He calls Jibreel, saying: 'Indeed, Allah loves so-and-so, so love him.' So Jibreel loves him, and Jibreel calls out to the inhabitants of the heavens: 'Indeed, Allah loves so-and-so, so love him.' So the inhabitants of the heavens love him, then he is granted acceptance among the people of the Earth." And Allah's love for a servant comes from his seeking the pleasure of Allah Almighty by performing the obligatory duties and avoiding the forbidden acts.