I am another very happy Elizabeth user and cannot imagine upgrading it. I have no interest in pressure profiling beyond what the Elizabeth can do with pre infusion. Now, since you are the only drinker and want to stick to a budget, going with a single boiler machine can have advantages. Sure, you have to wait a bit to steam your milk, but in terms of cost and footprint, a single boiler would be just fine. You will make great espresso. The Victoria looks like a wonderful machine with a professional sized group and PED, and similar programming to the Elizabeth. Unless you are making back to back drinks a lot, you will be happy with that machine I should think, and save some money for sure. And, they are much easier to maintain and descale when needed.
Now, the dual boiler with regards to temperature stability can’t be beat, and workflow is great. I moved up from a Breville Barista Express, which is really a nice entry level machine complete with built-in grinder. As a starting place to learn with it was terrific. But, the grinder was a significant limitation for dialing in coffee easily, as was the temperature stability. I learned enough to realize I needed something better to get the café quality drinks I wanted. So, I upgraded to the Niche Zero grinder and the Elizabeth, and unless these machines fail, I will not upgrade beyond that point. I drink milk based drinks and make a few a day since my wife has to have them too. This machine has been just superb, and really easy to live with in terms of cleaning, maintenance, livability. It sips electricity, can be left on all day, and you can turn off the steam boiler too. It heats up in just a few minutes if needed. Most importantly, it makes great coffee.
It is easy to get caught up in all the high end kit discussed in forums like this. For some this is a passion and a hobby. Indeed, these machines are just lovely and fun to use. I get it. But, you can make really good espresso with consumer grade machines and grinders. As we say in the USA, keep your eye on the ball! For me I needed to spend enough to make really good coffee that was easy to do and repeatable, with workflow and livability in the equation. So, I went with Niche and Elizabeth. That still set me back like $2300 USA. It has been well worth it for me.