Covid-19 are the disease with symptoms.

Yeah, okay. Technically COVID-19 is the disease. But colloquially, you get a "COVID-19" test and people know what that means.

Without symptoms you do not spread the disease due to low viral load,

That's not true. There are many cases of asymptomatic people spreading the infection.

"Combined, these baseline assumptions imply that persons with infection who never develop symptoms may account for approximately 24% of all transmission." - https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2774707

but you can spread the immunity.

What?

The SARS-Cov2 virus can be everywhere, and you probably had it a several times.

I probably haven't.

The symptoms are very similar to the flu and were mixed up a lot.

Yes. For less serious cases.

The tests of Covid are really bad, with 95% to 100% false positives.

Nowhere near that high. PCR tests for SARS-Cov2 are most likely somewhere in the 0.8% to 4.0%, which is the interquartile range of the studies aggregated for this paper, looking at false postives in SARS-COV2 tests: https://www.medrxiv.org/content/10.1101/2020.04.26.20080911v1.full