OMG as much as I appreciate all the confidence you put in me, my outdoor vegetable and flower gardens are kind of a survival of the fittest experiment, lol!!!
I live literally in a stormwater settling basin with shit clay soil that has as an amendment 2 years' worth of leftover cannabis dirt, hahahaha!
As for the peat humus, I'd check the pH- I'm 99% certain it's on the acidic side but I'm not sure how bad- in which case lime would be helpful, but of course keeping it just a touch below 7-
Clay soil is the most evil shit and I'd just keep rototilling whatever you can get your hands on into it including leaf compost and I might even add a little sand (urrr someone will probably laugh at me for this) just to make it a little more friable.
I love outdoor gardening but don't take it much more seriously than trying to lay it out so it's easy to weed and the plants don't shade each other at maturity- the only exception being my herb garden, which I actually took some care with because it's got some perennial shit and stuff that needs excellent drainage, so I put it on a fairly steep slope so even on the clay substrate it would never get waterlogged.
I grew both sweet peas (in the clay dirt, they survived fine, would have been better if I had weeded around them even once, lol!!! legumes are easy!) and chives (in the herb garden, now uprooted and residing in my neighbor's kitchen!) last year.
Sorry I can't help more, where's Latewood when you need him!?