i'm in the "Mesh works great if you use it right" camp.
i use a u6 pro which is wired to my u6 pro in meshed in my home office to devices that don't have WIFI (desk phone, PC, etc...), and a u6 lr+ which is wired to my U6 mesh in my garage which is meshed and have no issues. there's also a U6+ meshed to give better service to another part of the house (i didn't give it AP priority). both my wired AP's are in the basement (front and rear of the house), and both meshed AP's that are in the house are on the second floor.
my cameras on the garage, what i do in my home office, and everything else on my network doesn't care what which AP it's on, works for what i need.
I have the same problem. There is form insulation everywhere, I can’t punch new holes in the walls or ceilings.
I deployed the In-Wall 6 and Mesh 6s. The in wall in the office and primary bed room. Two Mesh 6s in the living room front of the house. Blanket coverage.
The things that stink are consumer level hardware and using wifi as a network infrastructure. Most of what you describe is due to those two things - cheap design and construction and iffy firmware for the hardware, and the general inadequacy of wifi to provice a reliable pathway, since it's subject to distance, going through something other than air, interference of several kinds. You don't care about speed - fine - but speed (on a node) is a consequence of weak signal, or interference. So, those two things - speed and reliability of connection are tied together.
There are other solutions aside from mesh to reach an outbuilding. Ethernet cable, fiber optic cable, point-to-point radio - all are better than trying to stretch a mesh somewhere far away. In general, when placing mesh points you do not place the mesh where you need the wifi, you place it in a spot that gets a *great* signal from the base router and the clients get a *good* signal. The link is more important than the client. That makes it impractical to use for jumping a bunch of space between two buildings.
Eero seems to get the most positivity for pure mesh systems. The plethora of offerings by the major consumer mesh manufacturers (Asus, TP-Link, Netgear, D-Link) shows how they would rather keep pumping out new devices than actually make something you would love to own. In fairness to them, wifi is no way to run a network infrastructure but consumers demand it. Wifi itself was designed as a convenience for portable devices, and convoluting it into network infrastructure was not a good idea, but one driven by the need for sales and consumer demand (plus consumer belief that wifi is somehow better.)
u/Scotty1928 makes a good point - I also run UniFi. If I was confronted with your issue (of the outbuilding), I would probably first try an outside AP on the house (outside - and you'd need to wire it to your network.) The AC-M is a particularly good UniFi model for this) and see if you get an acceptable signal at your outbuilding.
It's really not a lot worse that something like Asus, who has a decently robust interface (lots of consumer stuff hides everything behind "simplicity"). The payoff is reliability and a long service life (my oldest UniFi AP is 7 years old, still supported, and still working great.)
In consumer world - Asus and TP-Link are the better choices. Eero is great hardware has a subscription model for some needed (IMO) features. I would avoid Netgear, D-Link and Linksys - they are not what they once were and have subscription models, sometimes poor support, and varying reliability and quality. You could also consider gl.Inet Flint devices if you're looking for an all-in-one router, they have gained a very good reputation.
I agree that a better choice than any of the above would be Ubiquiti UniFi and TP-Link Omada is also decent - it's different than the consumer gear. Reliability is one of the major points of these prosumer setups. I've been running UniFi for 7 years, it's great.
I like ubiquiti, their U6-MESH APs are pretty rock solid for the price.
Side note: do you have coaxial ports in your apartment? I lived in an apartment for a few years that had coax ports in the walls that ran back to the utility closet with the water heater and they were all connected together so I was able use moca adapters and get that sweet sweet wire hard wired speeds anywhere in the apartment. Food for thought
Bolinious
