I recently (about 5 months ago) have taken up the hobby of playing piano. I'm following the Alfred Basic Adult Level One book. Really loving it so far but I keep messing up when it comes to one aspect of playing it. As you read in the title, I recently purchased the yamaha psr e463 (was using a friend's keyboard before) to practice the piano. I find it very difficult to play dynamics on it. As you might know, the keys aren't weighted and are super easy to press. However the loudness does vary depending on how hard I strike the key. But still, it's hard for me to get a nice smooth rhythm to any of the pieces that I'm practicing. Is this just a problem with the type of keyboard I've purchased or is there a particular technique that I'm not able to get a handle on? And yes, I'm a completely beginner and am teaching it to myself. I was going to a teacher, but that all stopped cause, you know, pandemic and that.
Spring action keyboards can be difficult for getting a good feel and dynamics. I looked at an online manual for your keyboard and found something that might help you. On page 52 of the manual there is a section called “Changing the touch response of the keyboard”. There are 4 settings but “fixed” is useless unless you want all the notes to be the same volume. Try 1-3 and see which you like best. You should be able to find one that works best for you.
In case you don’t have your owners manual here is a link to an online manual: https://usa.yamaha.com/files/download/other_assets/9/1170809/psre463_ew410_en_om_a0.pdf
One other thing to mention with this type of setting, sometimes the setting is saved when the keyboard is turned off but it’s possible it may default to the factory setting and you have to set it each time you turn the keyboard on. You’ll know when you try it.
I think you have more than one problem here.
The first problem is that non-weighted keys are not designed to be played in any way except fully-on or fully-off. It's a design that comes from church organs and has followed on through other organ designs. You can try to train your fingers to do this, but it's not going to be as successful.
The second problem is that having trained your fingers to do this, you're going to have real trouble transferring to a "proper" piano. Much of what you've learnt as muscle memory, you're going to have to unlearn in order to play a normal piano.
The third problem on muscle memory, looking at the specs for your Yamaha, is that I don't believe it uses full-size keys. This is really going to screw you over if you transfer to a proper piano, because you'll need your fingers that bit further apart.
And the fourth problem is that your Yamaha is a 61-key keyboard. Of course the "dusty ends" of the keyboard aren't used that often, especially as a beginner, but you run into limitations surprisingly quickly on a smaller keyboard. Certainly by next year, if you keep playing, I'd be amazed if you weren't seeing a couple of pieces you couldn't play the top or bottom notes of.
For sure it has a lot of bells and whistles. USB recording, rhythm stuff, all those kind of gimmicks. And you don't need any of them! What you need is precisely one thing, and that's an 88-key keyboard with weighted action. In short, you probably need to stop trying to do something with your Yamaha which basically isn't going to work; and buy something else which will work.
The very cheapest weighted-action electric piano keyboard will be much better. Looking online, Gear4Music in the UK have an own-brand weighted-action keyboard which is actually cheaper than your Yamaha; equivalents probably exist wherever you live. It might not be the best weighted-action keyboard, but any weighted-action keyboard is going to be better than what you've got now.