It sounds like you currently have a hybrid, you want to step up to a road bike, and you have not gone for a bike fit yet.
I haven't gone for a Retül fit. In general, a bike fit should get you the parameters you need to adjust a bike to your desired position, and a Retül shouldn't be different. A fitter should be able to suggest changes to your current position - going from a hybrid to an endurance road bike fit would be one example. Many fitters should be able to assess your mobility and suggest exercises or stretches to improve key weaknesses that might affect your riding. Also, you don't need to limit yourself to Retül; you might find that you work better with a different fitter.
It will not tell you which frame manufacturer to choose. You need to determine this yourself. Unless you have unusual physiology, you probably can get an acceptable fit on almost all stock bikes. Frankly, if the paint and other branding elements speak to you and the price is acceptable, that's probably a good enough reason to get a bike from most of the major manufacturers provided you can achieve your desired fit coordinates.
In particular, a bike fit will supply (or you can ask for) a target frame stack and reach figure, which tell you the frame size to target, as well as a handlebar stack and reach figure, which tells you or the shop building the bike where to put the handlebar. For example, you might get your numbers. Then you tell the fitter that you decided on (random example) Ritchey Road Logic frame. The fitter might look at the numbers and say, that should require a 55cm frame with 20mm spacers under the stem and a 120mm stem at -10 degrees, and a zero setback seatpost. Some bike shops might be able to do this as well, but not all may.
That said, how we interact with bikes changes with time. Our bodies age, we lose function in some key areas, our desires change. If you're on the right size frame, you can usually accommodate the changes by changing equipment (e.g. maybe 5 years later you change to a 110mm stem or you raise the stem slightly). But it might be tricky to accommodate the changes - for example, I came to prefer a very forward saddle position early on. This rules out a few stock frames, and it means I need a zero-setback post - but some proprietary posts are expensive to replace. I should point out that people often get follow-up bike fits with time.
I raise this because you are jumping from a hybrid to a top-level endurance road bike. There is nothing inherently wrong with this, and it's your money. I will only point out that it is also an option to get a nice but not top-level endurance road bike, and keep riding and dialing in your position. If you do get a top-level bike, it's probably better to avoid models with integrated cockpits, which can be a lot harder and more expensive if you need to change the handlebar position.
