Custom Domain in SL: DKIM and DMARC setup

If I have a domain set up in SimpleLogin to forward emails and use the default DKIM and SPF of SimpleLogin service, do I still need to set up my DKIM and DMARC separately? I'm relatively new to this and have not explored some of the settings and I'm afraid it would mess up the SL service.

PS. I don't have a website and use the domain solely for SL email forwarding and so far I don't have issues with sending and receiving emails.

https://preview.redd.it/aw5vn3vm929e1.png?width=695&format=png&auto=webp&s=a1faf3335807433673a5aa4193d8daf73a434348