Am I reading you correctly? Purchase a resale Lagunamar and then enroll with a Westin direct purchase? Can you expound a little?
I'm currently being pitched a 1 br Nanea 51 (4530 VC points/1500 MF/81000 VSN) for about $50k
Once you own resale weeks, then you are obviously aware there is a resale market and the salespeople know that as well. Therefore, it is much harder to sell you a developer purchase so they have come up with this concept of allowing you to enroll resale weeks in Abound if you make a developer purchase. There are different nuances to this in Marriott and separately in Vistana, but the most relevant points here are:
(i) Lagunamar has good value both in Vistana and Abound in terms of Staroptions/MF and CP/MF.
(ii) Lagunamar resale was historically priced low compared to other Vistana weeks like Kierland or Maui where Staroptions can be used with a resale purchase (cannot do what with Lagunamar).
(iii) A Vistana developer purchase will turn it from a weeks-only ownership to be enrolled both in VSN and Abound, and
(iv) In recent years, Vistana required only a $10K developer purchase to make this "requal" happen while Marriott generally required a $25K+ purchase.
So, if you are willing to spend $50K on Nanea, you can attend a Vistana developer presentation with a few resale weeks in your back pocket and see what offer you get that involves enrolling those weeks. You'll probably end up with more points and it will cost you less money, but requires patience and planning.
Alternatively, buying a Kierland or Westin Kaanapali resale 2BR Platinum (~$15K-$20K) will also give you 148,000 that you can use to trade internally in ~20 Vistana resorts (not Abound). Those would also be eligible to enroll in Abound with a Marriott or Vistana developer purchase, but would provide substantial trading opportunities even without Abound.