Keep in mind I am no expert here (being a Master Gardener does not mean "Expert Gardener" LOL) so what I do is simply sort of trial and error, developed over several decades of home gardening.
I grow mostly tropical plants (orchids are my passion) but I also have a sizeable raised garden for vegetable crops. Since I am in the habit of customizing all my tropical plant mixes, I also customize my vegetable soil mixture. My formulae that I used for my raised garden was 1/2 top soil and 1/2 "Planter's Mix". I purchase planter's mix from our local Co-Op by the square yard and it is light and very organic. I wanted my raised garden to have good drainage. In the fall I throw out about a handful of Osmocote per 10 sq. ft. of garden. This is the standard 19-6-12, six-month formulae. I also have grow-bags and huge pots that I plant in. That mix is 1/3 milled sphagnum moss, 1/3 Black Kow, and the other 1/3 is half coarse perlite and half medium Douglas fir bark. I add a handful of Osmocote for (approximately) each 4 gal. of soil mix. I use the fir bark simply because I buy so much of it for my orchids, I have plenty for my potted plants as well. I would imagine you could use hardwood mulch instead of the Douglas fir bark, since the mulch is readily available from big-box stores. Try to find heat-treated mulch though, since that kills pathogens, seeds, and spores that might well be in the mulch.