Nice to see few appreciate the taste of the beef itself and really mask it with near mini meatloaves.
You may want to mix some of the two meats up. I would guess your ground meat is 80/20 or so. Venison typically has great flavor but very low fat. I would go with about 2/3 ground beef to 1/3 venison first to use up what you have on hand.
Seasoning wise I would go with stuff that really highlights the meaty taste or compliments very well without overpowering it. Salt and pepper could be just fine but I know you want more than that. You can easily drop the salt or most of it and add some dark soy. This will add to the beefy flavor without adding a soy taste. worcestershire can also be added in moderation instead of soy to give it a different depth. Onions are fairly pungent and soup mix is a sodium bomb really so I find a good alternative is to use finely diced shallots in their place inside of the burger. Bacon I find is good with nearly anything, just not inside of a burger unless pre cooked. I feel it really belongs on top if you want it or for a different take skip it, yet cook your burger in a pan with a little bacon fat. Hell I could go on but it is late, so maybe tomorrow. I will leave a few tips though.
1. mix the meat as little as possible no matter what you add.
2. do not really compress the meat much.
3. high heat and turn once.
4. if you do thicker burgers (more than 1/4 inch), press your thumb into the middle of what will be the top prior to frying. Prevents that annoying UFO shape.
5. if you get told to do a cheese filled one, consider just mixing small cheese chunks into the meat itself instead of a big blob that may melt out of it due to a sealing issue.
6. thick heavy pan, it holds heat better.
7. chill patties for 20 minutes or longer before cooking.
8. do not press down on the patties when cooking.
9. you can pre-salt the patties and not worry about liquid loss. Liquid loss in that case is just water. Less water = more beef taste (see aging). Just pat dry first. In reality though you will not see much loss if at all in 20 minutes unless you fill it with salt.
10. after it is in the pan leave it alone until time to flip. a crust exterior is tasty.