I’ve worked as a professional mastering engineer for over 20 years now, and my honest opinion is that with the technology available now, the answer is “Yes”.
Of course, as a mastering engineer I’d always recommend you take your music to a pro!
But I also realise that you may not want to – perhaps you want to learn how to master yourself.
You may not have the budget for mastering – or maybe you even want to learn how to be a mastering engineer yourself.
And, it’s all free !

Ian