That said I definitely strongly recommend against using anything UniFi based for routing/gateway tasks at this point (author mentions their AIO custom hardware UDM thing). They have significant issues now in WiFi and even switching, but at least remain kind of workable there. But the company has been an absolutely depressing development dumpster fire for years now and the trajectory still appears aimed straight down.
This is depressing to read because I worked a Ubiquiti before things got bad. The company culture took a huge dive when the CEO began removing executives and managers that were getting things done. The company was always weird, but when I started they were good about finding strong engineers who cared about networking and letting us build good products.
Everything changed when they tried to reoganize the company around the UDM and move development to China. The UDM reorg was so awful that employees and executives were leaving in droves. For months we couldn't even tell who was supposed to be in charge of UDM or UniFi because so many people left at once. I think we had 4 different UniFi lead developers get hired and then quit a few months later after the early employees all left.
Sad situation. Ubiquiti was a cool company that paid well and let engineers do good work when I joined. I still wonder why it had to fall apart so fast. The company was never perfect but it was sad to watch the CEO drive away all of the good parts of the company.