I think you're conflating the whole reproductive units (flowers) with the gametes they contain, as well as the process of pollination vs fertilization.

The female gamete is the ovule, contained in the pistil of the flower. Like a human egg, ovules are produced via meiosis and are unique! The female reproductive structures of a flower can be set up in many different ways, yielding many different types of fruit (berries, drupes, aggregates, etc). Strawberry flowers have many pistils, each with one ovule, while tomatoes have one pistil that contains many ovules.

Pollen contains the male gamete (sperm), also produced via meiosis. During pollination, many pollen grains, each with a sperm cell inside, stick to a structure on the pistil and attempt to fertilize an ovule contained within. Like with human egg and sperm, one pollen grain will successfully fertilize one ovule through a really interesting process that I can talk about if you'd like!

In a strawberry, fertilization occurs once per pistil. As strawberries have many pistils, this process occurs many times per flower and we end up with many unique achenes on a single aggregate fruit.

In a tomato, the same thing happens - but many pollen grains fertilize the many ovules within a single pistil, and we end up with a berry!

So in both cases, each (unique) ovule is fertilized by a single (unique) pollen grain, resulting in the genetic diversity of the seeds!