I will setup mail account and fix emails going to spam, domain mail

In most cases, without authenticating your emails, recipient servers have no trace that you actually sent the email and hence mostly landed in the spam folder.

Sender Policy Framework (SPF) is an email authentication method designed to detect forging sender addresses during the delivery of the email.

DomainKeys Identified Mail (DKIM) is an email authentication method designed to detect forged sender addresses in emails (email spoofing), a technique often used in phishing and email spam.

Email spoofing is when the sender of the email forges (spoofs) the email header's from address, so the sent message appears to have been sent from a legitimate email address.

Yes, You highly recommended to maintain your domain reputation and ensure your emails will not start going to spam in the future by setup security or authentication.