Glad you're enjoying the game. Yes, you can reach Strabo, Astrape and dig through the obelisk in the current free version.
The paid version currently offers one new facility (Pneuma), and the obelisk rework which does reset obelisk progress/completion due to how much it effects. Sometime in the next month or so, the paid version will update to v0.7 (which adds another new facility), and the free version will update to v0.6 (the current paid version). At some point before v1.0, the free version will stop being updated so the final content will be paid only.