What is the cname field otz._domainkey & 2nd a txt value I don't understand?

In my Domain DNS records I have 3 versions of this cname key and I’m not sure that all three are needed, nor do I know how they got there. I’m guessing they are used for shopify’s email system, which is only used for automated messages when a sale is made, etc. I use Mailerlite for emails I send. I looked in the helps but couldn’t find anything. Any advice?

otz._domainkeyotz2._domainkeyotz3._domainkey

dkim1.c0c8bfda8874.p162.email.myshopify.com

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dkim2.c0c8bfda8874.p162.email.myshopify.com

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dkim3.c0c8bfda8874.p162.email.myshopify.com

I also have txt record that looks like what I show below except the p= field is about 100 characters long and I have no idea what this is. Any thoughts on it:

20210806173304pm._domainkey

k=rsa; p=MIGfMA0GCS