glut of lentils....help with ideas!

Lentil-walnut salad: cold lentils, walnut pieces, carrots, celery, whatever (all chopped very fine), and a vinaigrette made with walnut or olive oil, sherry vinegar, dijon mustard, and chopped capers. Learned this one in a cooking school years ago, and just made it the other day.

Cook any for which you don't have any particular immediate need; freeze in 2 cup or one quart containers. I usually cook double or triple what I need as a matter of course, always with a bay leaf and a touch of salt. They can then be used down the road for soups or salads.

This article, though focused on quinoa salads, provides ideas you can use for lentils, too.
https://food52.com/blog/7941-how-to-make-quinoa-salad-without-a-recipe
Living in a cool marine micro-climate near the San Francisco Bay, we eat soup all summer (it's often that cold here!); I have a quart of puy lentils in my freezer now that later this week will find its way into this soup: https://food52.com/recipes/2348-lentil-and-sausage-soup-for-a-cold-winter-s-night
Which brings to mind, "The coldest winter I ever spent was a summer in San Francisco." (Mark Twain) ;o)

It might be too late to be pertinent for this particular batch of lentils, but I really like them as taco filling: fry up garlic, onion, cumin, a bit of cinnamon, and tiny cubes of potatoes, then toss in a handful of chopped walnuts and a couple big scoops of drained, cooked lentils. It works well with ground meat browned with the veggies too (I sometimes use about the same weight of meat as lentils).

I also soak my lentils. It isn't strictly necessary, but they cook faster and more evenly for me that way.

Lentil shepherd's pie: lentils, mushrooms, and spinach in miso gravy, topped with a layer or garlic mashed potatoes.

So what happened to all the lentils?

Don't soak lentils! No soaking required at all. Rinse, give a once-over for a pebble, and cook. Quick, easy, versatile. Just try and buy where there's high product turnover (though even that's not a guarantee).

I make loads of beans and lentils but have never made loaves or burgers with them. I've never eaten a 'legume' loaf or burger that was tasty (except falafel balls, of course!). Maybe someone has a recipe they know...?

a nice salad with a few diced carrots and onions and a vinagrette. then to make it really special, some crumbled feta cheese. so good.

I really like a recipe from Ottolenghi's book Plenty. Here it is on a blog: https://inthekitchenwithkath.com/2013/01/05/green-lentils-asparagus-and-watercress/
It calls for watercress, but I've substituted successfully with arugula as well.
You could also cook the ones you don't need plain, and freeze them for future use.

Along with soup, lentils make a nice salad (like many legumes).

I like eating beans as part of my breakfast, so undoubtedly, I'd save some for that purpose.

As Phil mentions above, cooked lentils freeze well, so there is no pressure on you to put it all in one dish or use them all up at once.

soup! with bacon. It freezes well too so you it won't go to waste. There are a few variations on line