Advice on 'nearly identical' domain names

Hi All, I'm hoping some of the minds on here will be able to help.

I am setting-up a business, and own the domain for the company name, which is two words. There is an established competitor in the field who owns almost identical domain, but with first word as plural.

So for example: (not these words of course)

- I own "PlumberTools"

- The competitor owns "PlumbersTools"

Do you think I should build out on this domain? For reference I was thinking not only in terms of SEO but in the wider sense - will I lose clients to mistypes? etc

If it's relevant, they appear to have a full site with sitelinks, whereas I was (initally at least) thinking to just use a basic landing page as the leads will largely come from offline work.

Thanks in advance