If you are not planning to go until March 2027, it's difficult to justify
DVC at all until at least 2026. If you bought now, you'd pay 3 years worth of dues (Jan 2025, 2026, 2027) before you even get to take a trip. Personally, I don't really see the value of direct for myself and in your case I don't really see a HUGE benefit either. If you chose VGF or Poly for example you still have 38-40 years of usage of two desirable, well-located resorts even if you don't buy in until 2026. When the 2042 resorts run out, you'll still have an 11 month advantage at your desirable home resort. That being said, the difference between direct and resale at those two resorts is not nearly as big as at SSR for example. So, I'd suggest BLT if you were interested in resale.
As for how many points to buy, I have zero use for a 50 point contract, with my family we will almost always be in 1BR or bigger and I'm not interested in managing a contract that gets me less than 4 nights at WDW.