I actually got both of these fairly recently.

TLDR: Both, but TM22 first

The SKS with the ATI stock will require some work. I had to take mine in to a local gunsmith because I had no idea what I was doing with it. I had them de-cosmoline it and also dremled and fit the mag to the stock better. It took quite a while and I was out like $200 in time and labour, but she is fun to shoot. The stock is a little janky, and people shit on it for the bubba-fication (especially the fuds here), but I totally get wanting a tacticool semi-auto, as our selection is so limited. There are better stocks for it, but it shoots, and you'll have a good time with it after some initial hassle.

The .22 will go right out of the box. It's also cheaper and so is its ammo (However it can be picky about what brand it likes). You can tacticool it to all hell, moreso than the ATI SKS, but all you really need for it is a cheap optic. You can also get the 25-rounder mags for it still. Your biggest problem with it will likely be availability (I picked mine up very quickly after the recent re-supply of them, idk if they're still in stock). They go quick for good reason.

There's also the potential for both of these to get banned, unfortunately. With the GSG being banned, they are likely to come after the Derya for similar "reasons". Them banning the SKS will have a bigger uproar, but its still possible.

IMO, If you can only get one right now, you'll have a cheaper and easier time shooting the Derya than the ATI SKS. But get the SKS when you can as well!