Hello there Mag and welcome! I can perfectly relate to your problem because up until about a week and a half ago I had similar problems and naturally I got frustrated too but there's one thought that just brings me back on track: A lot of people can have lucid dreams, I am just as human as they are therefore I can achieve it too. It might take me longer than others but there is nothing stopping me from it but myself.

I personally don't find WBTBing (+ WILD) easy as I'm having a tough time getting my body to relax through and through. Most of my tries are foiled because either my mind falls asleep too fast or I give up after a good while of lying still and being no nearer to a dream then when I started. I still try this technique whenever I can though because eventually I want to master it.
The other path I chose was to practice was ADA and frequent reality checks which seems to finally have taken root after about 2 months. I find this rather pleasant to follow since it's something you just have to do every now and then and you don't get frustrated when you do it. Especially when you are in front of a computer screen it's an easy habit to get into. I myself made a desktop background that says "am i dreaming?" and whenever I look at it it reminds me to take a moment to take in my surroundings and start questioning reality. Other options are post-it's, or actual notification that pops up every so often.

Now, as I mentioned, 2 months later I've just had my 3rd DILD in 10 days last night. Though I don't exactly remember how or what triggered my first LD, the other 2, I clearly remember, were a product of suddenly questioning the oddities of my dreams. Last night for example I got into a car with my gf, drove around and parked somewhere and when I got out of the car I was standing barefoot in the rain, so I asked where my shoes are, already feeling suspicious but not being quite there yet, and I was told by a DC that I had taken them off and thrown them away. It clicked then and I became aware of my dream.

So the best advice I can give you as a newbie myself is to keep doing whatever it is you chose to do, if you want to WBTB and MILD then do that and keep doing it until eventually you succeed and don't allow yourself to get discouraged. I personally like that safety net of ADA, so when your WBTB fails you still have a chance of becoming lucid in another way.

Best of luck to you, and remember if I can do it, so can you