I'm sure it's not hard to order samples of the parts which are not yet in production. But how about cost-effective Artixes and Spartans. Even if they're still in production, they're all snatched by big companies. Were you able to get any of these?
I didn't ask for them because I still have some left - I've bought a bunch just as those whole COVID stuff was getting serious, and so I expected shortages. I did get a few Artixes-100s off Ali just for the heck of it, and they all soldered and worked great (of course I baked them before reflow as who knows how they were stored). Have you tried contacting their sales?
BTW, speaking of shortages, I've noticed that Mouser now has max limits set for some parts - like STM32 chips. Digikey does this even more sneaky - it shows only 10 parts in stock, but in reality it's got more. For example, I've bought 10 pcs of
this part a couple of days ago, but "in stock" number never changed and still shows "10".
Also I've finally found a good replacement to TI power parts which I used extensively in the past, but which has become unobtanium for the most part over last couple of years, during which I ran out of most of my stock. Now I use MPS parts and modules, because they sell small batches direct with $5 flat shipping fee and short turnaround time (3-4 days), and keeps seemingly a lot of them in stock by limiting how much parts they sell to a single company, which is why it's perfect for R&D/small batches like I do. For large production batches you have to place an order as usual. And they also have quite a bit of power modules (DC-DC buck with integrated inductor) at quite attractive prices.