I main browser and wolf, for practice I play quick play. I can't think of any match up problems, just the lack of progress.
It's good that you have a main already-that's a big first step.
Something I did to get better was watch Smash tutorial YouTube videos. Here are a few I personally recommend.
Enjoy the videos and music that you love, upload original content and share it all with friends, family and the world on YouTube.
www.youtube.com
Don't binge the entire series of Art of SU vids, watch the first and practice what it tells you before moving on to part two, rinse and repeat. Highly reccomend these.
Enjoy the videos and music that you love, upload original content and share it all with friends, family and the world on YouTube.
www.youtube.com
Banana Boy is an amazing teacher. You should definitely watch a lot of his stuff including this, and it's actually really entertaining as well.
Enjoy the videos and music that you love, upload original content and share it all with friends, family and the world on YouTube.
www.youtube.com
Pretty awesome video on how to DI and SDI.
Enjoy the videos and music that you love, upload original content and share it all with friends, family and the world on YouTube.
www.youtube.com
Another great Banana Boy vid.
Enjoy the videos and music that you love, upload original content and share it all with friends, family and the world on YouTube.
www.youtube.com
Enjoy the videos and music that you love, upload original content and share it all with friends, family and the world on YouTube.
www.youtube.com
Finally, two great videos on the characters you're playing. (I've solo mained Bowser for a long time now, if there's anything else you want to know just hmu).
Branch out from these and find out which content creators you like the most.
In terms of training, I'd say get comfortable with your movement in training mode. Practice walking, running, crawling, buffered short hops, normal short hops, short hop fast falls, short hop fast falls with an aerial, etc. Move on to the next after getting one a certain number of times in a row, let's say seven or eight. If you can't get something immediately, take a break before you try again, however long it may be. Other things to practice would be RAR's, pivot grabs, combos like Bowser up throw forward air or Wolf down throw dash attack. Being comfortable with your character(s) is the single most important thing to learn in Smash, imo.
As
Bowser D.X
said, practice against CPU's, they aren't the toughest training partners in the world but they help you apply the things you practiced in an actual match on a moving, fighting target. Selecting the "move" CPU behavior in Training mode also helps, as this just makes the CPU move and dodge unpredictably.
Knowing frame data a bit also helps. Not saying you should know all of your character's startup, active frames, and endlag on every move-in fact, I highly doubt anyone does that. For now, just use
https://ultimateframedata.com/ to see what moves are the quickest, which can really help. For example, Bowser has a frame 6 out of shield option, which is extremely useful against attacks that are -7, -8, etc on shield.
After beating the crap out of level 9 CPU's, try and test your skills with
https://www.smashladder.com/. It's like Quickplay but way better. Just make sure you know how to set up an arena and find its ID and passcode before starting.
Last thing, you will most likely have to narrow it down to one character at some point. Bowser and Wolf are both very strong characters so you can't go wrong really. It doesn't have to be now, but if you find yourself at a road block further in the future, you may have to decide which is most fun, most beneficial, etc. and keep them. Trust me, this helps a
lot in the long run. For now, though, you can play both.
Finally, go to tournaments. Not the easiest thing right now, and I personally wouldn't want you too. People are just dumb, especially when it comes to Smash players towards hygiene. Online tournaments are not a great supplement but you can still learn a lot. Always remember to ask questions after losing, like "How do I deal with that move as my character?" or something like that. Don't make it too vague, like "How do I git gud?" You won't git a gud response. Make sure to get an Ethernet connection and LAN adapter if you can.
Over time you can do other things, like studying your replays and practicing more complex tech and combos. But that's it for now, this wall's big enough. Hopefully you become a better player because of this.