The Eric Andre startup sounds insane. Almost like a sabotage attempt on the browser. Fortunately I'm using the regular Opera, not GX. But unfortunately the splash screen is also time-wasting.
Startup speed is still an important factor for browser user-friendliness. Now pretty much every other time I open Opera there is unnecessary waiting time tacked on thanks to the splash screen.
Firefox also has a similar issue. They roll out a lot of updates, that apply when the browser is opened. But at least those automatic updates do something (not just a splash screen) and can be easily disabled.
The reason I use these different browsers is that I use each browser for different purposes -- e.g. I'm signed into different Google accounts on each, so it's easier to keep track of things. But to circumvent this, I can also just use different profiles on Chrome or another browser that still take startup speed seriously. So if I don't find a fix for this soon maybe that's what I'll start doing.