I think your question comes from a place of both a misunderstanding of what dominant and recessive alleles are is and what a punnet square represent. Sexual reproduction involves the combining of 2 haploid genomes to form a diploid genome. A haploid genomes contains a complete set of genes, so a diploid has 2 complete sets of genes. All genese have variants known as alleles. If an individual has 2 copies of the same allele, they are homozygous, if they have 2, they are heterozygous.

Dominant and recessive relationships are not about how a gene is inherited, they describe how the phenotype relates to genotype. An allele is dominant to another allele if it masks the phenotype of the recessive allele. For example, in pea plants round peas are dominant to wrinkled peas. This means that an individual that has the round pea and wrinkled pea gene allele (Ie a heterozygote) will have the round pea phenotype. It DOES NOT mean that the round pea allele is preferentially inherited. It is also important to remember that dominant recessive alleles does not describe the majority of traits. It is the first, and simplest, genetic relationship that was observed. Most phenotypes are polygenic, meaning there is a small contribution to the phenotype from many genes.

Next, A punnet square just tells you the expected genotype ratio of homozygous and heterozygous offspring given the parents' genotypes. If two parents are heterozygous for a gene (eg BbxBb) have offspring, the expected genotype ratio for their offspring would be 25% BB, 50% BB, and 25% bb.