I was really leaning that way but I could not get the the GRX crankset (it was a Tiagra) with the GRX groupset at the time of purchase so I went with Tiagra all the way around. Of course, I read from from some of these larger websites that said they were identical, so at the time of purchase, I had no worries. I've read a little more on it now and see that there are some differences but I won't lose any sleep over the Tiagra vs GRX 400. My gravel riding is pretty cushy compared to most others gravel riding. I live in Fla and everything is pretty much flat where I bike. I'm 57 and I don't for see doing any serious technical stuff. I just like flat gravel roads and leaf covered roads that meander through the woods. Hell, I'm riding a R300 (Tiagra/Sora) with 30mm tires right now and everything seems to do fine.