Often when registering a free domain it is under an untrusted TLD and for this reason it can massively affect SEO. Using untrusted TLDs such as .ga, .gq, .tk, cf, and .ml and others that are regularly offered for free, or even those offered for under £1/$1 such as .xyz are seen by search engines as being used more often than other TLDs for the purpose of scamming. For this reason, they don’t show very highly in search results until they are trusted by the search engine and sometimes this can take months!