Tower Mansion on Leasehold: Worth It or Avoid?

My wife and I are looking at buying our first place. I’m 36, been working in Japan for about five years, and I’m a seishain. Ideally we’d like to build a house, but our budget is around 80 million and my wife is very particular about design so we don’t want to force a custom build house if it means compromising too much. Because of that, I’m also thinking about buying an apartment first just to get onto the property ladder and have something in my name that we could sell later. We’re in Chiba and I’m mostly looking around Makuhari and Makuhari-Kaihin.

I've found a really nice tower mansion for about 60 million yen. It’s 11 years old, has great views, and is close to the station. The only catch is that it’s leasehold and the lease ends in 2045. From what I understand, I’d own the apartment but not the land, and once the lease runs out the terms could change. That has me wondering whether buying it with the intention of reselling in five to seven years is actually realistic, especially if the remaining lease drops below 15 years by that point.

What I’d really like to know is how leasehold apartments depreciate in Japan as the lease gets shorter. Does the value start dropping sharply once the remaining lease goes under 20 years, or does it become a real problem only once it dips below 10 or 15? I’m also unsure how banks treat mortgages for leasehold properties with short leases. Is it harder to get a loan approved or will future buyers struggle even more because of it?

Another thing I’m trying to figure out is what actually happens when the lease on a tower mansion expires. Is it usually renewed on similar terms, or do owners have to negotiate entirely new conditions? Does the building lose value completely or is it more like an old contract being refreshed? And finally, I’m curious how all of this affects resale potential in places like Makuhari, where tower mansions are pretty common but not all of them are freehold.

I’m really considering buying this apartment, I just don’t want to make a bad decision on my first property. If anyone has experience with leasehold tower mansions, depreciation, or resale issues in Japan, I’d really appreciate your insight.