You can search for local gatherings and go to those. There is a regional matchmaking section here, but you might be able to just google that. You'll be forced to play what they are playing though, which will probably require a PS4 or PC. You're not really going to get better playing against the CPU or your bothers(unless they start to take it seriously too), so it's either that or online play. I wouldn't recommend using wifi for online play either.
There is really no secret to picking up a new character quickly, but when you play against real, good player a lot, you get a pretty good idea for how characters are played. You can also study frame data to give you an idea of what is safe and unsafe. Obviously you can learn that through trial and error as well, but someone has already done that part and laid it all out for you.
The take away here should be that you really need to play against better players. And I would recommend looking into alternatives to wifi, such as an ethernet hub and a long cord, or a powerline adapter(never used it, but I hear it's better than wifi).
Nice. I understand about those games being featured. Could you please update the GGPO forum name and description to Fightcade? Fightcade replaced GGPO a few years ago. I know that forum doesn't get used a lot, but it would be nice for visibility sake. I just made an extensive thread there in order to hopefully help out newcomers who might want to try it out. There is a big update coming out for it soon too, so maybe that will get some attention.
I think Capcom is aware that GGPO is better and we want it. But they aren't going to use it when they have their own netcode, even if it sucks. I'm pretty sure the only reason their ports of older fighters have it is because they hired Iron Galaxy to do the ports, and they probably wanted to use GGPO. It just seems to be Japanese devs in general who don't want to use it. Are there any Japanese made fighters that have it? Not even the Yatagarasu devs sprung for it, even though they said they would.