Lots of different opinions on stocks out there, but I’ll give you my opinion. I like a the aluminum adapter from Lage with a double star ace side folding mechanism that you s designed to take an ar15 style buffer tube. Then you can use your preference of the many ar15 collapsible buttstocks out there (I like Magpul). As a side note, you can machine the end off of the buffer tube and store a copy of your stamp and “papers” in there. If you are going to shoot a red dot sight, this setup works great. If you want to use oem style uppers, you will need to put some of the Lage “wedges” in between the adapter and the folding mechanism to angle the stock down slightly (so you can see the sight posts). If you want to switch in between, you can use a cheek riser comb on the slightly angled stock to shoot the higher red dot sight. I actually have (2) Magpul butts, one with a cheek riser, and one without. It’s easy to switch them out when I switch uppers.
There will likely be others who will have very different opinions on this topic. My setup has treated me well. It is comfortable, and performs well when shooting matches.