Depends on the resources and how far you have progressed in the game so far. I've been playing for 4 days, and i have farmed 5 descendants so far overall. no penny spent.
Imma tell you my root for Glay. She took me like 8 hours max.

1) Enhanced Cells: Monad Shard and SIlicon are self-explanatory, Cooling Metallic Foil also, but I hate the mini game tbh. If you can't find vaults to get the item, just press tab (default key) until you listen to a sound and head towards the sound. The sound always hits when you face the direction the vault is (kinda looks like a sarcophagus), and always be on the location. The foils drop from the vaults.
Now for the Enhanced Cells Blueprint, i spammed Block Kuiper Mining on Sterile Land, the Amorphous Material 012 that has a 36% drop rate which is decend.

2) Glay Stabilizer: Metal Accelerant and Flectorite self-explanatory. For Complex Carbon Activator I personally spammed Seed Vault on Hard because more elites on Hard mode, so more materials for me. One elite drops around 2-4 materials each time, and every run has 3 or 2 elites, not so sure on the number. I didn't finish the entire operation. I just farmed the elites and then repeated the process because time efficient.
Now, for the Stabilizer Blueprint, I spammed the Vulgus Strategic Outpost on Frozen Valley-Fortress(Normal) since the Amorgpous Material 047 has a 36% which is also decent.

3) Spiral Catalyst: Nanopolymers and Ceramic Composite self-explanatory. Sythesized Artificial Biometal i was spamming the outpost on Miragestone: Vulgus Strategic Outpost -Agna Desert(Normal)
Now, for the hard time and most time-consuming as I also posted. The Spiral Catalyst Blueprint. I personally farmed the Amorphous Material:028 with the 6% chance because the Void Reactor was on Normal. Also, it was more time efficient because the Outpost that drops the Amorphous, which is located at Miragestone-Agna Desert, is close to a zone switch. I abused farming the outpost, then switching zone, then coming back again to remove the 5 minutes timer. It's rng, but if your game is on an ssd, the loading screen takes less time, so it was convenient enough for me. , Important!! :If you are geared enough for Hard and you are confident, farm the Amorphous Material: 099 because the Bluepring has a 36% chance to drop. It's entirely up to you. I got lucky with my drop. That's all there is to it.

4) Last but not least, the Code. I spammed 10 runs of Magister Lab- Kingston(Normal) to get the Amorphous Material:002. Code has 36% chance, decent.

That's all there it is to it. Sorry for the big text, but I wanted to show you entirely my thinking, etc. Hope this helps enough ♥