Do you forward mails from Google?
And when you can via UI, you need to use the full eml file, not just the content. Content-only will be spam due to its missing headers.
If you receive so much spam from Gmail, you should contact them.
If you forward from Google, well, what should I say? Don’t. The first hop can do like 80 percent of the filtering. Also Bayes and neural learning are kind of useless behind a forwarder. Not 100% useless but it will not work quite good.
When all of your spam comes actually from not-forwarded Gmail addresses: post these mails here, please. The full eml files.