These are obviously first world problems. In the end it is what gives you pleasure. Any of these machines, including your Gaggia, can make top notch espresso if paired with a good grinder and good coffee. It is, after all, just coffee. I upgraded from my Barista Express to the Elizabeth because the grinder was not good enough, and the temperature stability was also lacking, causing too many sour shots. But I learned on that machine, and really loved it for what it was. Upgrading to the Elizabeth and the Niche solved all of those problems.
This morning I made 4 latte’s back to back for my wife, son, his girl, and myself using my Elizabeth with fresh Verve Streetlevel coffee and the Niche Zero. Nothing could have been easier. I could have made 10. The workflow just goes, and the machine reaches temperature for the next shot by the time I have the coffee ready in the porta filter. After I was finished I did my quick flush with Cafiza. Wiped her clean. Lovely. Living with this machine has been great. Would the Bianca be better? I guess, but not sure how unless for some reason I wanted flow control, which I do not. And the aesthetic of knobs or levers might be nice, but my work flow with this machine is so good, I just do not see the point for my use case. I will not upgrade this machine unless for some reason there is a catastrophic failure. It is warrantied for 3 years anyway through Clive here in the USA. I am just about to 1 year with the machine.
So, ultimately you have to be happy with what you have, because it is really about that. No downside to the bigger machines that you mention, other than price and weight. Perhaps maintenance is a bit more with those, but you may enjoy it. These are all fantastic, including the Elizabeth.