Wifi signal will definitely improve inside the house.. by how much is super experimental.
Every building has somewhat different behaviour. I remember a comment from one wifi installer.. that some buildings are just black holes for wifi. Others work front to back without issues. On paper the two buildings might have some design but actual building materials and location of wifi is critical.
Factors to remember..
Walls are serious blockers to wifi. The more solid the construction the higher the signal attenuation.
So internal hollow plasterboard walls are lowest signal drop.. usually 5-6dBm.
Outside walls are different.. they usually have heavier construction. Worse they can use metal foil insulation or cladding of some kind. Even thin metal is a total block to microwave signal. It is a reflector.
For bricks or concrete the denser and greater linear distance of material absorbs more signal. Angles also are important.. an oblique angle means more material is passed through. Additionally moisture content can be higher.. water is a great absorber. That is why your microwave oven is set to 2.4ghz. The Generator and most IoT use 2.4ghz.
Everyone assumes any problem is signal from router to the outside generator. Many people forget this is two way street. They put huge effort into better routers.. whereas the problem could be the signal from generator back into the house.. for which no improvement is possible.
That is why my recommendation is to run a mesh node in a window that directly overlooks the generator location.
Even better run ethernet to outside point on the house external wall. Buy a suitable external AP. They are not expensive.
eg TP-Link EAP110 or EAP225 - outdoor. They are sold in both indoor and outdoor types. The outdoor ones are waterproof and designed for easy wall mounting. Even cheaper models can be sourced. But it should be specifically designed as outside wifi AP.
Anyway much of this is experimental. Suck and see is a great engineering principle. Not so good for buildings or bridges or aircraft but great for home wifi.
The other thing is to measure actual signal.. I use built in wireless diagnostics in a Mac laptop.. or a suitable App like Netspot.
Walk around the house and out into the backyard and actually measure how much signal you are getting. I presume you are doing this.. but you need to be scientific about it. Measure actual signal drop through different walls.. as that won't change with router or client.
Remember wireless travels in straight line.. especially at microwave band. (It does bounce around but that is more a problem than help) Think of the connection as an absolutely straight 4" pipe between the router and client.. in some cases any metal objects eg a mirror, in the way totally wreaks wifi signal. Small changes in location can work wonders.. mounting routers up high in the house so they are free of furniture, books and book shelving (often metal) and mobile water bags (humans). It is why professional wifi systems are usually ceiling mount.
Main rule of thumb.. when in doubt use a wire. No amount of science can overcome the wrath of the gods of the ether. At least 60% of all wifi installations is voodoo. You may as well get a shaman with beads and rattles and a few chicken liver offerings as science your way out.
