Tips for making lean ground beef patties tender? I have to eat 93% lean beef as part of my diet. I am trying to find creative ways of cooking it because throwing it in the instapot with some tomato sauce is getting bland. I'd like to try making it into a burger so I can pretend like I'm eating a burger. 

Yesterday I added some salt, garlic powder, chili powder, and olive oil to 12oz of raw ground beef, and mixed it up with my hands. I then rolled it into a ball and slowly pressed it into a fairly thick patty. I then seared both sides on high heat and then lowered the heat and covered it for a few minutes. The internal temp (assuming my thermometer was correct) was 120 degrees F which is what I read online was restaurant style medium rare. Unfortunately, when I forked off a piece of the patty, the insides of it were still mushy like the ground beef. It also wasn't very juicy or palatable like I expected.

Does anyone have some cooking tips on making lean ground beef as tender as possible when cooked? In my next attempt I will probably try to make a thinner patty, then pan sear both sides and put it in the oven at 400 for 6 minutes.
I use only 5% fat beef - which I would assume would be considered 95% lean, though the UK doesn't measure it that way.
I cannot abide fatty meat, but that's a topic for another day ;)

For me, a burger is 500g beef mince, an onion, either finely diced, or pre-fried [different flavour profile], 1 egg, a good handful of breadcrumbs [somewhere between 1 &amp; 2 tbsp, I guess] a little salt &amp; pepper &amp; often a hint of cayenne. You could get adventurous with a hint of dill or even some finely-diced pickled gherkin.

That will make 4 large patties or 6 - 8 small ones.
I shape to 'about 1.5x the diameter of the bun it will go in' to allow for shrinkage, maybe 5 - 7mm thick.

Grill, medium-high, one side until it 'looks done' [1], browning nicely &amp; bubbling any fat/water off - I've never measured a temperature in my life - flip it, give it maybe half the time again on the 2nd side. Cheese optional, takes about the same time to melt the cheese as it does to toast the bun on the inside.
 Done.
If you still find that dull, try a side of home-made cole slaw. Add to that a dash of Tabasco for an instant hit, or some coriander [cilantro] &amp; lime juice.

btw, there are a million things you can do with mince, even if many of them are tomato-based.
Chilli, curry [&amp; how many different curries are there?] bolognese, shepherd's [cottage] pie, meatloaf, meatballs, kofte, kebabs, stuffed peppers...
&amp; that's before you even think about chunks rather than simple mince.
Goulash, youvetsi, tagine, Ethiopian wat, rendang, Irish stew... the list just goes on &amp; on...  

Pick a different continent every day. [2]

[1] Until you get used to the timing, just break it in half when you flip it, so you can get a visual clue as to how far through it's cooked. After a while you'll be able to tell by just looking, or by poking at it with your finger.

[2] This is our family's cooking motto.