How can investors make themselves aware of company announcements that do not appear in mainstream media?

Most retail investors probably know about company announcements only when the contents of press releases are published by mainstream news outlets. Mainstream news outlets such as newspapers or TV will only report news that will interest many people (due to space or time constraints). Iconic large-cap companies (e.g. Apple or Tesla) are newsworthy, so these mainstream news outlets will publish the contents of their press releases in one form or another. In contrast, non-newsworthy companies will be ignored by mainstream media.

My question is more about the small or obscure companies that are not considered newsworthy by mainstream news outlets. How can retail investors know about the press releases of small and obscure companies when the contents of their press releases do not appear in mainstream media?

So far, I have identified a few ways:

• Regularly check the investors relations pages of all the companies that one is interested in.

  Disadvantage: too many websites to check.

• Subscribe to a newswire of a press release distribution company. Examples: PR Newswire, GlobeNewswire, Business Wire, etc.

  Disadvantages: different companies choose to publish their press releases through different newswires, so one will need to subscribe to many newswires in order to get full coverage; potentially very expensive.

• Subscribe to a single newswire that aggregates newswires from many press release distributors. Examples: Dow Jones Newswires, Benzinga Pro, etc.

Questions:

• Are there other ways?
• What is an economical way for a retail investor to be aware of new press releases? Is it by subscribing to a single newswire that aggregates many press release newswires?

(Answers need not be specific to the US. An explanation of the corporate news distribution process is most welcome.)