Emails going to spam or lost on route - need a check on my website hosting set up please.

I have people emailing me saying I never replied when I did. Some have the email in their spam folder but some have absolutely nothing. A couple of people I could only get through if I used a Gmail address instead of my work email. Have read several articles which mention DMARC and DKIM and I think I don't have that set up?

So I was wondering if someone could do a check for me how my emails are set up and see if there are any obvious problems. GoDaddy said they did a fix this morning on a SPF record. And also this morning I realised I had my website link in my signature as http and not https - so I changed that. But wondering if there is something else I can be doing. I am also receiving a heap of spam when I didn't use to and wondered if I have been hacked (I have changed routers recently). Also some SEO company convinced me that it was a good idea to pay for a one off website optimization and they did that but since that I get heaps of emails about SEO and never had that before. I think they did something that made me more visible in the end to SEO companies.

Can you help me get my emails delivered and also receive less spam?
Thanks.