I haven’t played the game, but I’m not allergic to spoilers so I basically know all and I don’t like the current ending / gameplay options. I hope DLC will either add or expand on current ones making them bearable to me.
Do you think it will go on sale again around the time they will release a DLC? Or should I buy now and wait?
If you know everything about the game and if you’ve played previous soulsborne and you just aren’t interested by any of it, then I don’t know if you should buy it at all. DLC won’t fundamentally take it from a game that you don’t like the gameplay of into one that you will, and you already seemingly have removed most of the novelty of the experience by seeing it all.
You’ll have to play it to access the DLC, probably a good deal of it, have you played previous souls games or soulslikes?