I think everyone likes what they like and can't be forced. I remember trying to be a Mesa guy back in the 90s. I got a Dual Rectifier and had a Single Rectifier. Sounded amazing but i'm a Marshall tone guy.
I definitely wouldn't get the 20IR based on what you have. As you guys know, I have one and it is an amazing amp. It can chug, great built-in clean, loud, etc. But you have amps with bigger tubes and you will miss that. An el84 tube amp kind of trims off tones and certain frequencies. Not a bad thing but for hard rock and metal, that is when you notice it.
I just got the Syn-2 and threw my SLO-II and Killer Kali modules into it. Then into my other new buy, the Fryette PS-2a with two 6L6 tubes. Here is the difference. The 20-IR sounds great with the Synergy modules. The Syn-2 into the Fryette sounds huge just hitting one power chord. It is like this huge distorted thud that is so inspiring.
Now I still can enjoy the Synergy experience but sounds like I'm leveling buildings in a Godzilla movie. Just huge sounding. I think if you go the Synergy route, just get so much more out of the modules I to a bigger amp. The 20IR is a great amp though.