Never go for building links through WordPress theme
Instead of creating own themes most of the time people buy domains that have hosting in it or the term web hosting in it and then they buy tons of word press themes. WordPress themes are mostly for little to no money. People buy popular themes and they get the first rank on google get traffic but after time they got banned. Think of the long term.
Never go for expired domain names
Buying a domain that has the bunch of links and high authority but its niche is different, altering it according to your requirement will rank you on Google but once Google figured it out, you would lose all efforts, money – you would get banned. It would not work in the long run
Never write the same content repeatedly
Update content that is already written and change it to 2018 to 2019 instead of repeating when you run out of topics. Simply delete the topics that are old, and none uses them anymore. Use Google Analytics to get the least searched topics. You can combine repeated topics. You will get more traffic this way.