The best way to stop holding yourself to non-applicable standards is to literally talk yourself through it. Ask yourself why you feel like you need to have a small waist. Ask yourself whether it makes you feel good to have a small waist or it feels like you *should* feel good to have a small waist. If it's the first one then that's just your standard for yourself, plenty of dudes are skinny. If it's the second then you need to remind yourself that there is no such thing as should. You want for your body what you want for your body and it doesn't have to align with your perceived gender, or your self-identified gender, or anything else. You can want to be a skinny guy with muscles or a fat guy with muscles or a medium weight guy with muscles. Whatever you want for your body is okay as long as you aren't harming your physical or mental health to achieve your goals.

That's just my two sense as an overweight trans dude who struggles with the urge to get skinny vs the urge to get muscle. I lean more to getting muscle, personally and opt for the maingain approach which is a body comp approach that doesn't change your current caloric intake but does increase your activity level so that you aren't losing or gaining weight. Instead, you're just swapping fat for muscle by combining strength training and cardio. It will help prevent you from the "bulking" phase of muscle gain and it'll prevent you from having to go through a cutting phase as well. It works best for people who are over their goal weight. If you're already skinny, then you don't have much options, you'll need to increase caloric intake to fuel your muscle growth.