Hi LotusGlow,
It definitely sounds like you are placing a lot of pressure on yourself. You are also not "behind" in any way. There are people who are 25, 35, 45, and older still experimenting to find what is pleasurable for them alone and in partnered sex. Firstly, penetrative sex or oral sex can feel very different for people than fingering does. Sex can also look like a lot of different things, many of which are also not talked about or shown in some porn and popular media. As it sounds like you've been doing, the only way to find what feels good for you is to explore but with an open mind and without expectations or pressure (easier said than done, I know). I want to echo what Carly said that there are people who do not enjoy certain types of penetration (like fingering) but enjoy other types of penetration, and vice versa. What feels good and you find pleasure in is super individual and can also change with time.
You hit the nail on the head there with what you said about wanting to bring back the excitement that the anxiety you are feeling is dampening. One of the biggest things that can press the brake pedal on pleasure is feelings of anxiety that can come from expectations or other worries. Pleasure also has a whole lot to do with the brain and what you are thinking about. So, are you finding yourself worrying about these expectations while you are masturbating?
I'm going to link a couple of articles here about pleasure and masturbation which go into more detail about the things I've touched on. Here are two great ones to get you started but we have a lot more articles and advice columns on the subject because you are nowhere near the first person to come asking about this!
Is there anything in these articles that resonates with you?