It really depends on how big the system you intend to build is.
If only a small number of devices and a small number of sentences in rhasspy then you may get away with a raspberry pi but don’t skimp on memory.
I run the above and more on a nuc with a Core-i3 gen 5 CPU and it runs very well but I have hundreds of devices and a very large set of sentences and slots in rhasspy.
As @rejoe2 says why not give your PI a try, if you already have one.
Migration of rhasspy, node-red and homeassistant are all fairly easy if it turns out to be too little.
If you don’t already have a Pi, then you may be able to find a reasonably priced NUC second hand that will pretty much future proof your setup wrt performance.
One common mistake people make is to assume because the above will run well for a few devices when they first start out, that it will scale to almost any size.
When you say you have no clue about NUCs, they are basically just small form-factor Intel based PCs.
They are generally fairly power efficient as they use similar speced components as laptops.
There biggest advantages are lower power consumption than a normal PC, run off a standard Intel CPU so basically everything will run without needing cross-compiled ARM versions (although the things you listed above all work fine on ARM). They will also allow you to run additional things that may not be ARM compatible.
The downside is they are more expensive than ARM based boards and a bit more power hungry.