PB, couple of things. I borrowed 2 of your posts to pass on to my peeps about the Ukraine war, I gave you credit without naming you.
On the slow cooker. I have been told I make the best pot roast. The red wine is fine, but you have to use a sweet red wine like Pinot Noir, otherwise it can add to the bitterness of cooking slow, especially with venison.
Also, a couple of scoops of brown sugar can really help, and if you are short on prep time, organic bullion will work, although I just spice it up the way I like instead.
Low and slow, I like to start mine the night before and cook it as low as possible, depends on your cooker.
Also, it is important to sear the meat. You can do it in a pan, but if you are doing a large amount of something like 5 pounds of beef, I do it in the oven. I splash the meat with some worcester, a bit of asian fish sauce, and some olive oil and put it into a preheated to 500 degree oven for 15 or up to 20 minutes.
Whatever you do, do NOT use wine that is more on the drier spectrum, has to be sweet. Half wine, and half water for me, and I like to have it all covered with liquid, or close to it.