Well, you’ll have a few weeks to decide, as no Destiny content is currently available for immediate purchase. Battle.net stopped selling Destiny content today, and Steam will not offer any Destiny content until Oct 1st, though you can preorder Shadowkeep. You may want to check out some videos on the Forsaken content, including the Annual Pass content, to see if it has enough value to you to warrant a purchase. Some of the content may be harder to complete once Shadowkeep launches, as fewer players will be in those activities, unless we see an influx of new players to those areas. Things like Reckoning have so few players active, that it can be difficult to complete a single run at times, in its current state.

The only things that are going free to play is the year 1 content. Forsaken and everything past you will still have to buy if you wish to play that content. When you say you didn’t get forsaken, it was not included with the first expansion pass, and was it’s own thing that you had to buy.