Fix DKIM & SPF settings on my Domain/ Email account

I have a domain purchased via IONOS. I am currently using gmail to send emails via the import account functions ( the MX records have not been changed).

I am sending bulk emails via GMASS and most of the emails sent to Gmail recipients are bouncing as I do not have DKIM or SPF features activated.

If this is something that you can address please let me know how much it will cost to do and what you will require access too. I still want to continue to send emails through my Gmail account. If you think it would be easier to transfer my domain from IONOS to Google domains, please do advise.

I would like this task to be addressed as soon as possible.