Domain Name Keyword Advice

I'm making an amazon affiliate site and was wondering (in 2019) how much weight the keywords in your domain name carry over into the SERPs. I dug through the previous questions on this sub about the topic but it didn't really answer my questions. So..

Say I'm gonna be trying to rank for the long tail "what is the best toothbrush".
I get that whatisthebesttoothbrush.com would be ideal, but I'm planning on having more than one of these lists for this domain. Would (all other things being equal) naming a site whatisthebest.com or thebestofeverything.com toothbrush.best have any effect at all or is it an all or nothing thing?

Thanks, Fam

besttootbrush.com

I usually skip exact match domains when looking for a keyword as most of the time these sites are kind of spammy, it's 2019 and having a more brandable, not so obviously generic domain is preferable and generate more trust in my opinion.

So, for example, for the keywords: best tooth brushes 2019

• best-toothbrushes-2019.com

This one above doesn't look too trusty.

It would be better something like:

yourdentalfriend.com, dentalexperts.com, Happyteeth.com,
Gumsandteeth.com, dentalcoach.com, etc, etc

That's always been my instinct.
And hey, thanks. I appreciate it.