Having setup problems - best to put everything on zoho??

Having setup problems - best to put everything on zoho??

I bought a domain from google domains (smithhome.us) a month or two ago.  I have also signed up for ZOHO free email and have trieded to get everything setup correctly so everything works.  I am new to all of this, so getting the DNS settings at google domains has been a learning experience.  So far I have these entries:

Name    Type       TTL         DATA

@            A          1h           74.201.155.96

@            MV       5m          10 mx.zoho.com

@            TXT       1h           “v=spf1 mx include:zoho.com ~all”

www     CNAME    1h           zhs.zohosites.com

Some of the problems I'm having are:
  • google domains won't let me create the "20 mx2.zoho.com" record, saying it's a duplicate
  • I get errors using the MXToolbox tool showing missing or invalid DMARC record.  I think I need to add an DKIM entry, but don't know how to do this
  • I can get to the website using "www.smithhome.us", but not just "http://smithhome.us".  I think I need to setup a naked website redirector, but not sure how to do it.  [My A record above is my attempt to fix this]
  • I get a https certificate name mismatch from the MXToolbox tool that I don't know how to fix.
  • I think I also want to fix the reverse DNS does not match SMTP error too (from MXToolBox}.

So, are these problems something I can get worked out between google domains and zoho, or should I just transfer my domain over to zoho so that everything is simple?

Thanks for any advice or help!