Please explain how to counter Yasuo as Galio or Swain

I've read a few times on the forum that Galio and Swain are Yasuo counters, but my personal experiences haven't matched those statments. Sadly, Galio and Swain are the champions from my mid champion pool that are listed as Yasuo counters, so I'm hoping I've just been trying wrong and somebody can explain to me the correct way to fight against Yasuo as one of these two champions. I'm going to briefly explain what I do as each champion, and if anybody can tell me how to improve, please do.

Galio: Galio is actually my main champion for mid lane, so this would ideally be my best bet against Yasuo. My build path for Galio is RoA > boots > Glacial Shroud > Spirit Visage > Frozen Heart > Merc Treads

My problem with Galio is that both his Q and E are skill shots and both are blockable by windwall. I can kill a crappy Yasuo, but I can do that with any champion I'm decent with. A skilled Yasuo will just walk up and start harassing me and last hitting minions, and if I do anything even remotely resembling a cast animation, dash through a minion to avoid it. In the rare cases, I manage to hit him, it only pops his shield and he walks around to regen it and come back. If I ult, my R enough won't do enough damage to kill him and he'll just dash through me or the nearest minion to avoid my follow up. The only way I can actually get kills is if my jungler comes while my R is up, but this isn't countering him; this is just what happens when your jungler ganks any enemy. Fortunately, I'm good enough with Galio that I can use my W to avoid getting killed, but I can't really get kills own my own against Yasuo. From my experiences, Galio doesn't counter Yasuo; he just goes even with him.

Swain: I was actually very excited when I read that Swain was a counter cause I love Swain, but he only really seems to do good against a small set of champions. But to think one of those champions would be the one who I have the most problems with got me excited. My build path for Swain is RoA > Zhonya's > Sorc Shoes > Rylai's > Abyssal

I've only gone up against Yasuo as Swain once and I didn't really know what to do so here's what happened. At level 1, I had my E and he had his Q and I managed to win trade offs by E'ing and AA'ing. The fact that I was winning at level 1 got me excited and I figured I was going to do good. So level 2 came and I got my Q and he got his dash. I figured that if I was winning trades with E and AA, then my Q would just do more damage on top of that. So I went in for the E and Q. While I did land it, I sure as hell didn't win the trade. Now that Yasuo had his dash, he just dashed through a minion, AA'ed me in the face, Q'ed, and started chasing me as a ran. When I got out of range, of his autos, he just dashed through me and started wailing on me again. I went from full life to about 1/5 of my life and while I did take off some of his life, his lifesteal managed to negate hafl that damage just by the damage he did to me. I had to go back and when I came back, he was already at full life from his lifesteal and ready to go again. I spend the rest of the time trying to avoid any path he could dash through and jump on to me, but that meant I was unable to do any damage to him. And unlike Galio, Swain has sub par wave clear so I was just falling behind the entire time. Once I got to level 6, I decided to just try the full Swain all-in combo and see what happens. My E and Q hit, but obvious my W missed cause it's Yasuo. but my E, Q, and R weren't enough to outdamage him, and he just killed me. There was absolutely not coming back at that point. I have absolutely no clue how Swain is a counter to Yasuo.

So if anybody can point out any flaws in what I'm doing, I would appreciate it. I'm almost sure there's something wrong with how I played Swain. Maybe build Zhonya's before RoA and just risk running out of mana for damage. I don't know. That's why I'm honestly asking for help.