porco_rosso Okay. I love acoustic pianos. In Germany I could buy a young (80s, 90s) german upright with the size of 116 - 124 cm of a brand as Schimmel, Grotrian-Steinweg, Ibach or a slightly older (60s, 70s) Bechstein upright for 6000 € - even at good piano stores. Here in Berlin someone at ebay kleinanzeigen sells privately a Steingraeber & Söhne 124 (!) for 6999 € from the 80s in perfectly fine condition. There are plenty of nice pianos here. Availability and price are not the problem. I would be perfectly content with the sound and the action of such an upright. I also have the space (even for grand up to 2m).
But I live in an apartment. A total of 9 residential units live in my house entrance, including a friendly policewoman who often works night shifts and understandably wants to sleep in the mornings. A nice young couple lives above me with a baby who is only a few months old. Below me is a very nice single mother with a behavioral problematic, sometimes aggressive son. Everyone is considerate of each other, that basically works well. And now I'm supposed to (and I've already tried it with a rented Hailun upright...) rob the policewoman of sleep after a night shift in the morning? Or wake the baby in the afternoon? Or upset the boy with repetitive practice of individual passages (he's sick and can't help it) that it is even more difficult for the mother? All of this is much more important than my piano playing. And even if you agree upon on a golden time window from 3:30 p.m. to 4:30 p.m., you don't have exactly that time every day, and an hour is not particularly long if you buy an instrument for thousands of Euros. I would have to move away if in doubt. But that really is not an option. Acoustic pianos are just too loud. I could not play them.
Your description shows a certain unhealthy character trait: You make the problems of strangers your own problems. Sharing a house with people doesn't mean you have to share your life with them. You don't choose your neighbors, but you choose who you share your life with. You shouldn't know all this stuff you mentioned above. You need to set boundaries or you will run into mental health issues at some point.
For example some of us have neighbors too, with some of them having an extensive (noisy) sex life, but if you start thinking about if your neighbors are satisfied with it, that's none of your business. And it's the same with your piano practice.
Overall you are in pretty great spot actually. Where you live an apartment is not considered being a "sleep cell" only like in Japan, the home of the digital piano. Singing and making music is considered being part of living at home, because unlike Asian ant countries, you're not considered to exist only for commuting between work and sleep.
The human voice and acoustic instruments are privileged, as they are allowed to make as much noise as they are physically able to. Only if you introduce electronic amplification, you're limited to the volume of the human voice (and you're supposed to run all your electronic gadgets at that level: your TV, your guitar amplifier and of course your digital piano). But there is no landlord preventing you from putting a concert grand in your flat or simply singing fortissimo after work. Of course, we are considerate people, so we don't go nine-footer, but with a reasonable 42" upright.